Devcon 4 report: Day 4

Previous days:

Today is a shorter update. I spent a lot of time in meetings with different tools teams (Truffle, Zeppelin, EthPM) about how to better do contract upgrades in a DevOps manner. Expect more from me once I get it working and write it up 😉

Internet archive

Brewster Kahle

Distributed web version of IA

Told a story where back in the day they started taking Bitcoin, so they had some young guy come in and help them set up their initial wallets. It was Vitalik 🙂

Instead of the world wide web where we have lots of blogs, everything has collapsed into Facebook and Twitter. People are building castles. The web is being turned into a global surveillance tool
Internet Archive is getting involved in the decentralised world to help try and affect change.
The goal is: Universal access to all knowledge. Want to be the library of Alexandria version 2.

He loaded up
Showed that the first HTML page is a bootloader. Loads up the JS libraries to access IPFS, torrets.
Browsed around the site, loaded videos. It all just worked.

More privacy. Reader privacy, and no third party storing of data.
People being rounded up based on what they’ve read, has always led to bad things.

13 challenges (I missed some)

  • Naming of decentralised websites
  • Permissions, auth and key management
  • Identity & reputation
  • How do you manage & name mutable data at scale?
  • The web beyond advertising: who will pay for what and how.
  • How do we make the decentralised web work in browsers today
  • Storage in the DWeb
  • Governance in the DWeb
  • Defining D-terms
  • Rethinking UI and UX for a decentralised web

Money is the killer Ðapp: crypto in Venezuela

Venezuela has issues with their currency and government controls and corruption.
Bitcoin is the most liquid in Venezuala, about $1m being traded a day.
Crypto is being used for:
Earning across borders.
Storing value (safer than banks)
Defeating extortion, when crossing boarders.
Providing aid to families in different locations.
Open money initiative. They have a wiki for Venezuelans to use and learn how to use crypto

Self-Sovereign Sexuality

Ameen Soleimani, Chelsea Palmer

Will talk about how the Ethereum community, and the sex worker community are aligned. It was easier to just take a photo of each slide for this talk, as they have written down for each aspect how they are alike.
Where is blockchain adoption going to happen first? He realised that this community that has been ostrasied from traditional financial system was a great place to start.

About a year ago, he was feeling pretty depressed. Wasn’t spending time on Tinder because he was working a lot. He wasn’t having luck talking with girls and was getting more and more nervous over it. He had a lot of money and was lonely, so started looking up sex workers in his local area. Made a meeting with a local escort. But when he went to get cash out, he was at his daily ATM cash out limit. He couldn’t get enough money out and had to change his 2 hour apointment down to 1 hour. He met the escort, talked about crypto, got her on board, and paid her by cypto.
Morality does not equal legality.

Was a sex worker. Wish she had crypto back when she was working. Now she is a crypto educator.


Needing to trust and verify.
Vetting a new client for first time, need to get a referral from another escort. Difficult for 1st time customers.

Sex workers are cypherpunks. They use proton mail, loads of crypto currencies.

Sex workers can be immediately blocked by most traditional financial systems.
Sex work criminalisation, currently stops sex workers from calling local police if they have things to report. As it is more likely that they will just be arrested than helped.

Devcon 4 report: Day 3

Previous days:


Building the Ecosystem for the Next Wave of Users


Creating a story and personality for what you build
They found that adding a background and story behind the cats helped with the adoption. The breeding concept gave a good anchor point.


Users were burning gas without realising. Were sending 10x more gas price than required.
User education and guidance was required quickly after launch to help teach.
Adding more feedback after a transaction to the user to make them more comfortable. Sending emails when things happened and what will happen next after breeding cats.
-Users need guidance when they’re in unknown territory.


Teaching a user that is interested in the service, that they need something called a wallet, they need cryptocurrency. Bit of a learning curve.
People came to the service because they wanted to buy cats. But now they’ve got a PhD in cryptoeconomics, which is not what they were after. Created a massive drop off rate of new users through the signup process.


Making the Web Distributed Despite Itself

Dietrich Ayala, Mozilla

“We are committed to an internet that promotes civil discourse, human dignity, and individual expression”
What does it take to be a 100 year organization.
The web is ~25 years old, and its not going to well. Being used a misinformation platform, fueling hate.

There is WAY more information and web apps available online via web browsers, than there are available via apps on iPhone & Android (~5 billion pages).
URLs are what made the web powerful and universally accessible. Urls are understood by technology people, but “normal people” don’t really know what a web browser is, or where things are stored. Same with domain names.

What does re-decentralizing the web look like?
Current web is centralised. Browser request, response. Easy to censor.
All the power resides on one side, on the server. The browser doesn’t have any say.
While we have that centralisation chokepoint, we won’t be able to get away from centralised services like Facebook.

How do we go about creating a decentralised browser to give control back to users?
Need to think how to build things for century long longevity. Whatever we build now will need to be supported.
Start with protocol primitives that can be built up on.

How do we get those lower primitives prototyped and built, so others can start building higher level primitivies
As a browser vendor they could do it as part of the browser engine, or JS APIs, or extensions. Makes sense for them to do it via extensions, to give everyone a bit more flexibility while experimenting

Announcing libdweb extension


IPFS team took it, got IPFS running in it. Got IPFS running completely within a browser.
But now they have a bunch of new things they need to think about. What is the origin of a website loaded by a IPFS hash. This has an impact on local storage, cookies, certs, etc. What is the threat modelling for this.

Use what you make, if you don’t use it why would others. Build for the long web. The web was (originally) built with redundancy built in. Are there multiple implementations of your software.


Privacy for Everyone, Recent advances in privacy

Zookoo Wilcox, Zcash

Released Zcash 2.0, 4 days ago. “Sapling”
They reduced the time complexity required to generate a ZK proof down dramatically. Should enable them to be generated on a mobile phone now.

They did this by replacing the hash function that is used when creating a ZK circuit.
This reduced the time required by 75%. Took it from ~40secs to 10secs. But still too much time. So replaced some of the ECC functions used to reduce to 5 secs. Then did split circuit design to half it to 2.3 seconds.

One of the troubles they have had, is ZK-SNARKS required the “toxic waste” which was the secret string to provision the system. They went through an elaborate ceremony to create it to try and ensure that it could never be created by any 1 person at any time. But still has a cloud over it as you can’t convince everyone of it.
ZK-STARKS doesn’t have any “toxic waste”. But the proof size is orders of magnitude too big to be used in a blockchain in every single transaction.

They could try changing their Blockchain away from Bitcoin software based, to make it higher bandwidth so they could put in STARKS.

Common thoughts are “regulators are scared of privacy” and don’t like things like zcash. But the regulators in USA have been fine with it.
New York requires cryptocurrency companies to register for a “Bit license”. Zcash is the 7th cryptocurrency that has been explicitly approved to be used and traded, and they called out the privacy preserving aspects.

Previously SSL encryption was scary and governments were worried that it could be used by criminals, but is now required by governments. Blockchain encryption will probably be the same thing.
The regulators even told them “We don’t want the pocketbooks of our children and family open to everyone on the internet”
It is not okay for our society to go down the path where everyone’s privacy is read by 2 or 3 centralised services, it is wrong and dangerous.


Lex cryptographica : the legal challenges of new blockchain-based lifeforms

Primavera De Filippi

Properties of Blockchain:

  • Blockchain is a decentralised database
  • Networks are global and transnational
  • Blockchain is resilient
  • Tamper resistant
  • Transparent
  • Non-repudiable (need to use private key, can’t deny it later)
  • Pseudonymous
  • Guarantee of execution

Blockchain code can be written to include traditional law, it only cares about what the code says.
Code is trustless and allows disintermation and autonomy.
Conflict between the rule of code, and the rule of law

Governments use the law to put pressure on centralised companies via regulators to say what the code can do.
Can the new wave of crypto-anarchist effect change in the new decentralised web.
Traditional property rights. Are defined by law, and can be taken away by the law.

It is now possible to deploy Autonomous Agents. They can hold property, and can execute smart contracts.

Created blockchain based “Plantoids”. They can’t breed by themselves and need others help.

1. capitalisation. Collecting cryptocurrency to repoduce. It tries to loook pretty to encourage people to donate ether to it.
2. if it has funds, then it can ask people to vote on the new artist to create its child
3. it will use a smart contract to hire the artist to create the new plant model.

Artist gets royalties from how much the plant earns as an incentive to make good ones, and for them to breed.
Now instead of sending money to artists, you send money to the art pieces. A different funding model.

The plantoids can have requirements put upon them. Its children need to be based on its rules (requirements for decorative elements) and artists can put new requirements on the ones they create. Will make different species emerge.
Requires “Holographic consensus”
COALA (Coalition of Automated Legal Applications) is a global research initiative.



Decentralize, Democratize, or Die

Cory Doctorow, EFF

EFF origin stories from 25 years ago.
The original “crypto wars”. NSA put restrictions on civilian use of cryptography.
Gov tried to lock everything down to just DES-50 encryption. EFF tried to show that DES was insufficient and built hardware that could crack the entire DES space in 2 hours.
But govs said ‘well, we need it otherwise criminals will go dark’
The technical arguments didn’t work. So EFF posted the source code for stronger encryption online on usenet, then argued under free speech that it was fine. Was the way EFF allowed people to use encryption higher than DES-50.

Showing that there are more tactics in your toolchest than just “deploying code”.
Main ways:
Deploying code and hardware.
Markets. Getting partners to go in and argue.
Norms. What is socially acceptable. Moving encryption from just nerds, to making it mainstream.
Law. Whats legal.

You can’t make everyone you communicate with use crypto, something will leak
You can’t audit all of your hardware.
You can’t verify every cypher algorithm is solid and sound.
OPSEC is not going to save you. Security favours attackers. Defenders need to be perfect all of the times, attackers only need to find a mistake once.

Crypto and privacy tools can help protect and shelter you for short periods of time. Can help protect you while you have discussions that you aren’t ready to have public.
There are many things that used to be illeagal which are now embraced and considered normal (being gay, interraccial marriage, weed).
They happened because people could have secret communities that they could whisper and have secrets with people. Social progress was able to continue.

DMCA was used to stop people reversing engineering DRM.
So anyone what didn’t want you to modify hardware, would just put a tiny layer of DRM on top of the hardware. To make it impossible to modify without “breaking DRM”.
Insulin machines using cartridges that have DRM, so it is illegal to bypass the DRM to use alternatives.
Now that everything has a DRM chip in it, make it really difficult for researchers to do anything without it being illegal.
DRM in browsers. No browser vendor promised to not use DRM to prevent security researchers from disclosing vulnerabilities.


Attacking. You want to make it so that the cost of attacking a system, costs more than the expected economic return.
This works, until the value of the thing you are protecting suddenly goes up (such as a cryptocurrency suddenly spiking).
For crypto people, it means the cost you should put in to protecting your computer is going up, because the vaule of what you’re holding is going up.
This means new 0-days for attacking machines are becoming more valuable, as the expected return is going up as there is more chance you could find private keys.
The rule of law is the best way to get things changed. We love code, but need to find ways to help the law change towards how we want it seen.


P2P Networking in Ethereum 2.0

Jannik Luhn, Kevin Mai-Hsuan Chia

Very short session

Validators are a new class of node. Similar to a shard node but only downloads recent history, and switch between shards regularly and randomly.

Networking protocol requires 3 things. Discovery protocol for discovery. Gossip protocol to distribute data. And RPC calls to sync data history.
Gossip will pass things out to a few neighbours to help it get diseminated throughout the network.


They used GossipSub by libp2p (rather than devp2p).
Did simulations for 1,000 nodes to see how things would work. Found that nodes didn’t go over 60% capacity. None hit 100% which meant that things weren’t being bottlenecked.

Cranked it up to 10,000 nodes

P2P implementation
They are using libp2p. Allows them to switch out the protocols like TCP, etc
Requirement for the networking layer was that clients should be able to subscribe to one or more shards. And the client should only receive data for shards it has subscribed to, and not others.
They have implemented the essential funcions like joining sharding network, subscribing to multiple shards, etc.


Managing upgradeability and EVM packages with ZeppelinOS

Facundo Spagnuolo, Open Zeppelin

Tutorial blogs are online

ZeppelinOS. Open source platform to help you build smart contract systems.


How to do upgradeability
npm install -g zos
zos init my-project

Write the smart contract (MyWallet contract)
zos add MyWallet
zos push -n ropsten
zos create MyWallet -n ropsten
> 0x23abba13

Later find there is a bug in the wallet.
Update the source code.
zos add MyWallet
zos push -n ropsten
zos update MyWallet -n ropsten
> 0xccab2314

This is all done using proxies
ZeppelinOS provides a standard way to fix bugs, and add new functionality.

EVM Packages
EVM packages are upgradeable on-chain packages of smart contract code

Can have your code depend on other packages and link to them. Later they can be upgraded.

How do we know these packages online are correct? ZeppelinOS Vouching system.
Will allow users to back the quality of an EVM package. Signal your support. First step towards a curated on chain packages system.


Unscrambling an Egg: Decentralization and the Zcash Foundation

Josh Cincinnati

Are we decentralised yet

What is the goal, what are we really after?
Zcash want to be used for the public good. The foundation is there to help guide and make sure the zcash company are on the right path.


CBC Casper Design Philosophy

Vlad Zamfir


“Correct by Construction” protocol design is a process of protocol specification which guarantees that the resulting protocol definitions satisfy desired properties.
As opposed to a process of iterated trial and error.

He spent 5 minutes talking about defining undefined, and how you can define the most undefindness you can have. I just got lost (a common theme throughout this talk)

“Bottom times bottom, is more defined than bottom”
“bottom times empty set is more defined than bottom times bottom”
(you can see why I’m getting lost here)

CBC protocol design, goes from defining the most simple things, and then define things on top of the previous definitions.

“sometimes CBC design isn’t quite straight forward”

The beauty of using CBC, is that the protocol is defined by the definition. Means there can’t be ambiguity, it just does exactly what it says it should do. Makes it easy to prototype and test, and things just work.
Thinks like not needing to worry about consensus protocols as much, as it all just work out. Showed an example prototype where shards can just keep becoming the new root that others build off, and them continuously rotating around with new roots.


Ethereum 2.0 randomness

Justin Drake


They use randomness in 2 places.
One in sampling to select validators.
Can also be used to expose randomness to EVM apps.

Goals for randomness is to make it unpredictable, unbiasable, and unstoppable
In RANDAO proposers are given slots. And they can reveal a secret to seed the randomness.
Gives the last revealer 2 numbers to pick from, the current random seed, or what they would add.

Verifiable Delay Functions. Takes an input, difficulty, and outputs the value and proof.
Can chain them to make it harder to bias

Need to make sure that good actors can calculate it within a threshold of attackers. They are thinking of creating VDF ASICs that can do it, and then handing them out to many people.

To create the initial random seed that will be used for the VDFs, they will use a RSA creation ceremony with 1024 participants. Just need 1 party to be honest to be successful.


VDF ASIC hardware
Doing it in partnership with Filecoin!


LibSubmarine – Temporarily hide transactions on Ethereum

Prevent reordering attacks. Keeps data private temporarily, can’t see who or what is being committed
Can add it into contracts fairly easily. Can modify ERC721 to add a “sealed bids”


Off chain you generate a submarine address and generate a merkle-patricia proof. Then on chain execute a transaction to commit the submarine tx, and then later reveal the proof.


The Entire History of You Is Being Sold

Jesse Leimgruber

In the USA there are 10,000+ companies currently pooling and selling your data. And it isn’t even being kept securely as Equifax showed. Data leaks are becoming more common occurrences.

Users need to own their data (Bloom app stores the data on your phone)
Limiting access (user is responsible in selecting how it gets shared)
Data reusability. Good UX to allow many apps be able to reuse the data.
They just partnered with BMW to use Bloom for BMW loans.
Also announced partnership with American Express to use bloom for their loans.

Devcon 4 report: day 2 – Ethereum 2.0 keynote

Other days:

Today had less sessions and was less intense. Apart from the keynote by Vitalik and SpankChain sessions there isn’t much to report on.


The MC wrote a song (I tried to take a video but was too far back to get anything good, I’m sure there are videos online).

He is tokenising his songs and putting online

Welcome to Devcon 4

Aya Miyaguchi, Ethereum foundation

Ran through her history of learning about blockchain & Ethereum.
Ethereum has a chance to empower society with it’s decentralisation, but we need to protect against it being used to restrict people by centralised powers (traditional companies and gov). Important for Ethereum community to keep these values as we scale.
Ethereum foundation keeps on making sure it minimises power in individual people. It wants to see itself as helping connect and foster collaboration in the community and connecting dots. But its goal is to grow the Ethereum community, not itself. Is why it didn’t structure itself in the way of a traditional startup or corporate.


She has invited a number of special guest speaker for the week. Like the internet archive

Ethereum 2.0

Vitalik Buterin

It is the 10 year anniverary of Satoshi’s Bitcoin whitepaper.
Ethereum 2.0 is a collection of research projects that have been ongoing over the last number of years.
Back in 2014 he wrote a paper on how slashing could be used in a “proof of stake algorithm”.
There was a bunch of aborted research in 2014 around different scaling mechanisms. Poof of proof of work, Hub & spoke chains, hypercubes.

During 2015-16 was a bunch of quiet research.
Resarch on “consensus by bet”. Some people would bet, which influence others to bet on those blocks, until one of the blocks have enough backing.
Wrote a scalability paper in 2015.
Wrote about the “data availability problem”. Could allow malicious parties to not publish data, which is required in sharding.
Everything got stopped in 2016 after the DAO attack, and the Shanghai DOS attacks.
But still quite worki happening on ewasm.

First Casper FFG paper came out.
At Devcon last year he showed the new sharding design.
Vlad released Casper CBC paper.
End of 2017 they released a Casper FFG proof of concept of a hybrid proof of stake system. Would allow gradual upgrade and migration. This research got very far.
But meanwhile there was a lot of working happening on Sharding. During a retreat in March they had a lot more details solidify. But they realised that there were teams trying to implement hybrid proof of stake inside existing blockchain, then a separate group that is trying to make a sharding system and a validating contract. The 2 groups weren’t really talking to each other. Realised they could reduce a lot of work if they just integrated them better.

It did mean that they lost a bunch of work that had already been done. But it meant that it would be simpler, and be better integrated, and the final state would be much better. (I think they did a great thing being able to step back, not worry about the sunk cost, and made the better overall decision).
Meanwhile LOTS more research happening on things like cross shard transactions and contracts.
Development happening on beacon chain implementations.

Ethereum 2.0’s real name is “Serenity”.
Gets us closer to it being “the world’s computer”


Phase 0 will be part way between main net and test net. The beacon chain will be there and running, but can’t really do anything with it directly.
Phase 1 will do sharding of data. NOT sharding of state. Could do decentralised twitter on the blockchain. But no smart contract applications.
Phase 2: enabling state transitions (smart contracts)


Track overview

Layer 1 (sharding, casper), Layer 2 (state channels, plasma, sidechains), ZK-SNARKS, light clients, etc.
Suggested sessions:
Making sense of layer 2 – Josh Stark
Snarks for mixing signalling – Barry whitehat

Ethereum 2.0 sessions


Designing robust systems


Lots of centralised companies are harvesting our data. We need to take the web back.
Suggested talks:
LibSubmarine – Temporarily hide transactions on Ethereum – Stephane Gosselin 
Plugging the metadata leaks in the ethereum ecosystem – Peter szilagyi

Developer Experience
Suggested session on EthPM

UX design
She just flicked through many session names. Nothing jumped out.

Society & systems
Technology changes society. And society can influence tech.


Events around Prague 

Decentralized development, what does that even mean?

Amber from Clovyr

Web 3.0 is about trying to keep data close to where it resides, decentralisation, data portability,


Development of blockchain clients (Bitcoin, Ethereu, zcash). Funnily enough the core code contributors of those clients are centralised in just a few developers hands. But if you look at something like kubernetes they have sooo many more people contributing.
How about code hosting, 90%+ of projects are all hosted on Github.

Browser 3.0

Mist team.
Current browsers are owned by centralised companies who track (Chrome, Safari, setting default search engine, etc).
Metamask extension was removed from Chrome store for a while. Chrome apps all got killed off.

Lets build our own. Lets start by using Electron.
Current web3 clients on the desktop are Metamask, Brave, Ethereum Mist, Parity. 3 of those 4 were built on Electron. But electron has a lot of security issues which is a bad thing for crypto private keys
Electron keeps lagging far behind the latest versions of chromium, meaning it is vulnerable to known exploits for long periods of time. Mist team don’t want this so they are building their own electron alternative called Tau.

SpankChain: Payment Channels in Production NSFW!


Their “pegged” stable token is called Booty.
It all goes into the “spank bank”.


Took 4 attempts at payment channels.
2nd, the MVP. Was a unidirectional ether only. Issues they had was that querying infura was non-deterministic, and Truffle timeout was 240 seconds which meant things failed in production.
3rd they launched. They got hacked when they unlocked their geth node for the deployment. Was only unlocked for 140 seconds and lost all the funds in that wallet.
4th they upgraded it. Had p2p virtual channels, ERC-20. The contract got hacked “they got spanked”. Worked with the hacker to fix the bugs.

The rewrote the smart contract and the UX. There were issues with the original version trying to get adult performers to join payment channels, as they’d need Eth to pay the gas to run the transaction. So Spankchain would need to send the performers enough gas before the show starts, to open the channel. And then do the same again when they close.

Announcing “ComeSwap” to cash out your booty for Ether

Devcon 4 report: Day 1 – core tool updates

Other days:

The first day of Devcon started at midday, but still had 12 talks. It was a bit of an “updates” session. The main event kicks off tomorrow morning with the keynote by Vitalik.


  • Universal Ethereum Logins was the show stealer for me. The demo blew me away, and there is a full SDK available now to use.
  • Lots of research into switching from Devp2p to libp2p (the networking stack IPFS uses)

EF Grants update

Ken Ng giving an overview of how EF grants foundation has been going since the launch this year.

So far has given out $11,000,000 to 75 projects over 4 waves!
Grants program is to fundamentally empower the Ethereum community and open source development. About creating up the core Ethereum platform, for others to build upon.
Want to help people build their passion projects that will help the Eth community. There will be more waves of funding, be sure to apply.

Ethereum Mist

Everton Fraga from Brazil

Submitting transactions looks scary at the moment.
Currently revamping the transaction window with a lot more details

Syncing improvements. Instead of a full sync, do it in stages.

Ethereum Name Service

Nick Johnson


Making it easy to attach friendly names to Ethereum addresses.
Rolled out with the .eth support with traditional DNS.
Rolling out 2 new domains .xyz & .luxe

Permissionless integration via DNSSEC
Can claim now via or you can use EasyDNS

More researching is ongoing for the registrar. They found that a lot of the names are being owned by just a few people.
Moving to a “yearly rent” style model to prevent squatting. Also help pay for ongoing development

There will be a migration process over to the new domain registrar. If you do it within the first year then you get a year renewal.
Otherwise if you don’t migrate it after a year, the name will be released.


Adding support to into client libraries like Web3.js 1.0, ethers.js. And other projects like Gitcoin.
They are developing a new Dapp interface. It is much slicker and easier to use.


EthereumJS – Our roadmap for 2019

Is an implementation of most of the base Ethereum technologies, implemented in JS (EthVM, merkle trees, etc.)
Used by Truffle, Metamask, Embark, etc.


Ethereum JS virtual machine. 
Is a “web first” library, embedded in Remix and Metamask. Captures Ethereum’s state transition rules.
Looking at integration with ewasm, but there are difficulties in EthereumJS being completely async, but the current specification for ewasm is synchronous.

Ethereum JS client
It isn’t meant to be a R&D platform for new features and research efforts. An educational tool.
The architecture is inspired by bcoin 
It can currently sync to the main net (fast & light syncing).
In browser can sync via libp2p.

Ethereum JS Sharding (ShasperJS)


For the phase 2 Ewasm research, is taking a list of ordered transactions and executing them.
Why Shasper in JS? Because it’ll need to be written and supported so the other tools can use it.
Not much real info in this session.

EtherTS (Typescript)
There are lots of EthereumJS that is written Sync, and lots written async. Want to take the learnings from the last 2 years and implement them.
They started by using Typescript to help find bugs by pointing out type issues
*cheers from the crowd for using Typescript*
Will be using more Typescript in the future.


Zlex Beregszaszi, Solidity co-lead.

It is a “Language for language developers”
Last year he did a talk on Julia, but there was a naming conflict, so now it is Yul.
Easier to just show the slides for this bit. They are helping compilers build better code.
Is currently being used by Solidity, Flint, LLL


Making ICOs fair (Reversible ICO)

Fabian Vogelsteller

He has helped build a few important things, like Ethereum wallet, mist browser, web3, ERC-20 standard, ERC-725.
Tokens allow you to own them, and transfer them.
Just a smart contract with an internal list of account balances.

What triggered the ICO explosion was the way that smart contracts could call and integrate with each other. Could creating funding contracts, token issuance, etc.

But people greedy. Were collecting a LOT of money, but maybe without having a solid basis for the proposed project.
So how can we make this more fair, what makes a Fair ICO?

Vitalik wrote an article on “DAICO” as one possible solution, was based on voting on the funding flow from the pool to the developers. Problem is people don’t vote.

Reversible ICO

Funds are given over time based on a “tap”.
Everybody can send his tokens back and get the “not yet given” funds out.

1. allocation phase. Committing funds to the project.
2. distribution phase. Funds are released slowly over time.
2.1 if at some point you think the project has gone off course, you can withdraw your tokens and get back your (not yet given) funding.
3. Swap phase. Swap out for utility tokens to use the final project, or final shares, etc.

He is going to try it out with his own ICO for


SWARM Team update

Decentralised file storage.
Session is a collection of team updates

Warning: <My yearly rant as they never make any real progress>

I still do not understand why they don’t just embrace IPFS as the base decentralised file store layer, and then build Ethereum specific extensions on top of this. It would help ensure there is a critical mass of decentralised file nodes, faster connection times, resolution, etc. Not only that, the community has been building on IPFS for the last 2 years.

The ONE interesting part they were doing was the SWAP/SWEAR/SWINDLE incentive layer. That would have been a great research project to put on top of IPFS, and leveraged what is already built. But this year they didn’t even speak of the incentive layer!

They are just reinventing the wheel, and have delayed their own progress by YEARS.

New release process. It is now in the same repo as geth. Whenever there is a geth release, there is a swarm release.
Whenever there is a swarm release, the nodes at are updated to newest version.
It is easier to install now. Can get via apt-get, docker images, binaries.

Is a pub/sub system.
Is a key/value store.
Each user can only update their own key space, but can read other key spaces..
Could be used for IoT data feeds.


Rolled their own encryption algorithm.
Took an existing crypto algorithm and “tweaked it”.
Missed a screenshot of their variation.

I’m sure nothing has EVER gone wrong with writing your own encryption algorithm.

Access Control
Does it by encypring the data, and giving keys to just the people that should be able to access it.
Accessing content which is “access controlled” is enabled ONLY when using a local node.
Don’t use a public node, as they could read anything you have access to.


Metric logging for swarm nodes. CPU, memory, number of peers, etc.

“yet another messaging system”, why this over Whisper?
Focuses on efficiency over secrecy.
On by default, can’t disable.

Light Node
Only briefly connected clients that spin up, let a user do something, and then usually disappear



Universal Ethereum logins

The bad UX experience of signing up first time to Ethereum is terrible. Requring taking selfies with your passport to sign up for an exchange, to get buy Ether, etc etc etc.
The UX is so bad, that there were more ICOs this year than daily average Ethereum users 😉


Showed an awesome demo of onboarding a new user, completely in browser. No keys or ether. Really watch this session for inspiration.




After Devcon 3, Implemented a libp2p version as an experiment.
It works, but the GO implementation of libp2p isn’t very modular and brings in a LOT of dependencies. This needs to be resolved before it is rolled in.

Devp2p was the Ethereum team created protocol.
Libp2p is the one used by IPFS.

Currently they have implemented libp2p next to existing devp2p implementation. Will slowly migrate it across to libp2p and remove the devp2p stuff.


The are working on the Moon project (This was my #1 thing from last year).

Moon browser: Instead of traditional accounts and passwords, uses crypto signatures.
What if you could fork an entire web application. (not just the front end, but the eth contracts as well).

To enable this, Dapps need a formal specification. A spec of everything this Dapp promises to do.
So to enable moon browser to do something like this they needed to solve this problem.

They looked at a bunch of existing formal spec languages, but non fit. And all were slooooow.

So they created their own called “Formality”

Devp2p development update

Felix Lange, Maintainer of the devp2p specification.

It’s a p2p networking stack.
Doing experiments on running devp2p apps on libp2p. Have an idea how to integrate libp2p into devp2p.

He seemed a bit defeatist. “yeah there are a bunch of implementations. Pretty much all Ethereum blockchain implementations”
State of live network. “Well we’re still alive”.
Development update. “This is where we usually talk of what we did in 2018. We finalised writing up the spec! And we have a test suite now”
Geth p2p changes. They implemented mitigations to a responsibly disclosed denial vector.
Sharding research is mostly being done on libp2p at the moment. Peers need to switch quickly for sharding, which doesn’t work too well in devp2p right now.

Special projects

Dr. Virgil Griffith

Is a grab bag of links to cool projects.

  • Moving nash equilibriums.
    Prisoner’s dilemma is non-cooperative. But can change to cooperative if they both pony up a deposit.
  • Created a new frontend for EF grants
  • Created a new wiki
  • ethereum gift cards
  • peaceBridge. ETH-ETC bridge.
  • They just gave Ethereum Classic a $150k grant.
  • can help you create wolframe code. Can use it as an oracle to calculate big numbers
  • Using Intel SGX on desktops, allows you to use any desktop PC as a hardware wallet.
  • helps protect your staking machines in future.
  • The Crypto Paradise of the Caribbean

Resolving IPFS API CORS issues

I keep being hit by this issue when trying to configure my IPFS node to allow programmatic access to the API.

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://localhost:5001/api/v0/add?stream-channels=true. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing).

The answer is to configure the API permissions of the IPFS configuration.

ipfs config --json API.HTTPHeaders.Access-Control-Allow-Origin '[\"*\"]'
ipfs config --json API.HTTPHeaders.Access-Control-Allow-Methods '[\"PUT\", \"GET\", \"POST\"]'

IMPORTANT: After making any configuration changes you need to restart the IPFS daemon in order for the new settings to take effect

I had gone wrong as I had been trying to change the GATEWAY.HTTPHeaders instead of API. I also didn’t realise I needed to restart the daemon.

Community report: Smart cities Blockchain hackathon

I was proud to be a sponsor, trainer and mentor at the Smart Cities Blockchain Hackathon

SmartCitiesHack Melbourne brings together the brightest minds to develop innovative solutions, utilising IOT, Blockchain and Big Data to introduce smart technology to solve real world problems, in one of Australia’s largest cities.

An impressive aspect of the hack is that there were 2 teams from a girls high school, one from a college, and one solo university student. It was great to see younger people getting involved and solving problems from their own unique perspective.

The final demos that interested me the most were:

  • Home stay invest
  • Public works platchain
  • Smart space

And of course there was lots and lots of food sponsored by Microsoft


Kick off

A few guest speakers presented at the beginning of the day to help give insights into what type of challenges cities are facing. One of them was the CIO of the city of Palo Alto

Cities of the future need to focus on 3 key things: Liveability, workability & sustainability.

6% of Australia’s GDP goes through Melbourne
How do you prepare a city for autonomous vehicles.
Digital identity. Who owns it, who can use it.
How can gov policy keep up (some industries will be dead before legislation even comes in)

We have such a massive influx of people moving into the cities. If we think traffic congestion is bad now, wait until the future!
Thinks the issue is climate change trumps any other issue.
Users don’t want to deal with governments in giant waiting queues at centrelink. They want to just pull out a smartphone app and renew their license.


  • 3rd place. My Say
  • 2nd place. Owl
  • 1st place. Smart space



The presentations

Smart space
Decentralised way to list rentable spaces e.g. conference rooms, lecture theatres.
Can book it using blockchain, get a QR code, can enter the room.



Team peak
High school student team
Medical insurance fund
Do it peer to per so that you can reduce costs by removing the massive admin overhead costs of existing insurers.
Have people in community randomly validate claim requests.



Property storage rental.
More and more people are moving into cities, people have less living space. People are looking for storage spaces. Allows people who have spare space to rent it out to others


Smart carbon
Solo 2nd year university student.
Tracking carbon emissions from sensors, and keeping a true record on the blockchain. Built a blockchain solution that would allow sensors to store their data. Allows trusted collection of carbon emissions in real time.


Public works platchain
Try and reduce costs and provide better cost certainty through public works tenders.
Tenders and implementations rely on multiple parties (council, telstra, contractor). At the moment parties can delay without incentive to complete on time.
Can use blockchain as an escrow account for payments, and other stakeholders put in a deposit. If the contractor delays, they automatically get a penalty fee taken out of the escrow account. If the stakeholders (council or telstra) are the cause of the delay, they lose a portion of their deposit.


Team Quatr
Tracking home rubbish bin levels, so that garbage collection trucks don’t need to stop at every home, and can be more efficient. Automatic optimised route creation.
People that recycle get 1 “eco token” per recycle bin collected.


Home stay invest
For international students looking for long term housing. And for Australian’s looking to purchase an investment home.
Allows people to invest in their communities and their schools.
Multiple actors, students, people that want to invest, people who have spare rooms to rent.
Fractional property purchase / fractional sale.



Team Owl
Sensors can create streams of data, that they can sell for tokens.
Others can see on a map the list of streams, can click to purchase access rights to the sensor data stream.
Iota IoT network


Team Mysay
Girls high school team
Electronic voting via the Blockchain. Allow more open democracy. Can use for local council meetings for example

Devcon 3 report: Day 4 – p2p tech

Other reports:

Today’s sessions covered a lot of secure messaging (Whisper / PSS), some swarm, and a couple of sessions on real world supply chain / logistics applications

Whisper: Achieving Darkness – Vlad Gluhovsky
Imagine a world where defensive technology always won. World would live in harmony. Lots of harmony and liberty for all
Want to help “achieve darkness” with whisper.

Whisper is a messaging system designed to deliver darkness at high cost.
Darkness is when no meta-information has been leaked. Plausible deniability.
Is an integral part of Ethereum. Off chain. The underlying Ethereum communication protocol takes care of delivery. It is a gossip protocol. Every message is delivered to every node.
Message is forwarded on, node can’t decrypt it, passes it on. When the message does receive a message that is for them that they decrypt, the node still passes it on so that no one knows it was the final recipient.


Spam prevention uses proof of work.
Ephemeral identities. Decentralised. Built in steganography. Darkness
Is high latency, high traffic, high processor load, high memory usage. Need to try and decrypt messages even if they aren’t addressed to you (is the only way to find out if it is to you).
The topic is 4 bytes of arbitrary data. Used for probablistic message filtering. Will be used for routing in version 6. Topic collisions are expected and required for plausible deniability. Is just there to help you get a subset. But you don’t want to reduce darkness too much.

Recipient: should forward all messages
Sender: maintaining noise by sending random data sometimes. So that metadata isn’t leaked by only sending messages when it is a real message.
One directional logical channels
Can do symmetric and asymmetric encryption.
Whisper is tech agnostic. Can use on any network.

Need to pad messages with random data to not leak metadata.
Additionally you can use steganography to hide messages in the “random” message padding



Using Whisper and IPFS to improve customer experience in a P2P marketplace – Michael Thuy, Stefaan Ponnet
Consumer facing dapp without users worrying about blockchain, EVM bytes, etc.
Will talk about creating IPFS consortiums to help ensure data is pinned and available

If you want to create a Dapp which is completely decentralised, you still need storage. Need to make sure data is retained long term on IPFS. Got people in an IPFS consortium who help out by cross pinning each other’s data to keep it retained.
Created a IPFSProxy.sol contract to handle the cross pinning.
Contract that has functions to add and remove hash and broadcasts events when hashes are added/removed.
Run a proxy listener on IPFS nodes to know what to pin/unpin.
Other contracts can call the contract to add/remove pins.
Can trigger a pin via a couple of mechanisms e.g. whisper
Individual supporters can run the proxy script at home.


Gas station
a way for users to get some gas to be able to use Dapps. Most Dapps are solving this by giving some free gas via a faucet. But difficult to restrict it from being abused.
Made a contract that holds eth/gas, can swap tokens for gas.



How to build a real world supply chain ecosystem using the Main Ethereum Network – Giuseppe Bertone

Easier for you to read his slides than me retyping it out



Building consumer facing interfaces for trust in supply chains
is from Consensys.
Give consumers on the supply chain of an item. Disclosing how you make your product and the craft that goes into it.
Based on verifiable claims. The claim and the verification are 2 separate things

Bringing verifiable claims to the supply chain.
Business claims. Could claim you are independent or family owned. Could claim this by linking to your company registration.
Organic certification requires getting a person to come out to your farm, check the process, then give you a PDF certificate. Show that PDF to other companies to prove your organic status. Gives you the rights to put the logo onto your products.
Moved the organic database into the blockchain. Can move from just a logo on a pack to something you can scan and verify.


An issue they had in the old system was that more fish were being sold than had been certified (fraudulent fish). They made an easier way for fishermen to register their catch on the blockchain, and then associate it to the fish.


For flowers, created an app so you could see the entire logisitcal history of where it has been.
Same with coconuts



Next batch of sessions I moved into the breakout stream for p2p technologies

[p2p] Breakout Session on P2P technologies: Introductory Remarks – Viktor Trón

Ethereum for the “world’s computer”
Swarm for the “world’s hard drive”
he called this a Swarm workshop. I may get ranty again.

Swarm has continued to grow in scope (feature creep) and is well beyond its initial spec of file storage.
Real time apps need communication, so want to build PSS
Need an incentive system, so are building Swap (this I agree with)
Are now creating their own payment channel system……..

there is so much scope creep!
Creating their own decentralised storage, incentive system, messaging system
Now they are creating their own payment channels?

I absolutely love and agree with the end result. But this team really needs to scale back, focus on the core value prop (Swap for node retention incentivisation) and do a lot more module reuse from other projects like uRaiden, IPFS, etc.



[p2p] – Swap, Swear and Swindle games – Viktor Trón, Aron Fischer
Framework to incentivise all distributed system.
Grew from a small micropayment system, to a more complete system.

Swap is the protocol which tracks what services are provided and consumed. Is on a per connection basis. Nodes keep track on usage of its peers.
Type swarm address bzz://somesite
Receive data from peers and compensate them if you consume more than you send back.
Can track the payments off chain. Can keep collecting cheques from a channel, only need to keep track and eventually push the last one onto the blockchain for payment.


Cheques are just a promise, not an actual locked in payment.
The system can be extended into a payment channel with stronger assurance.
Chequebook system can be extended to cover other forms of financial instruments. Bounties, bonds,

Swear is saying what services you can offer
Swindle contracts are the enforces of service promises.
The point of the swap and swindle game, is to securely list and provide services.



[p2p] – How Truebit can leverage PoW + PoA to solve for visa-scale transactions – Zac Mitton
Has been doing research on Merkle computers, as TrueBit
Ethereum scaling strategies.
Blockchain isn’t scalable, because all full nodes need to execute all transactions.
Solution is to find a way to not require every node to execute every transaction (such as sharding, side chains)

Truebit allows for provable off chain computation.
Break up the execution of the piece of work into many many tiny sub parts, each are small enough to be executed within the Ethereum gas limit.
Run it off chain, publish result to blockchain. Others can verify and challenge if they disagree. Then a proving game starts where both parties say at which point through the execution do they disagree. A billion operation execution could happen in 30 verification transactions on chain. The dishonest person pays the penalty.



[p2p] – Web3 Goes Live – Livestreaming Video on the Peer-to-Peer Internet – Eric Tang

Live streaming today needs a lot of infrastructure to support the bandwidth requirements, processing into multiple streams, pushing to CDNs. Large costs on bandwidth.
Peer to peer video can help reduce costs on popular streams by peer sharing.


The future is to move to a decentralised live streaming model


His suggestion is to use a crypto token service. The nodes that are providing service earn tokens. People use tokens to broadcast on the service.
Nodes can be supplying bandwidth. Or they could join the network as transcoders and offer that service for tokens.
Nodes can do the transcoding, provide merkle proofs for what they do. Can be verified, so that they get their payments (can use Truebit or Oracalise for example)



[p2p] – Streamr stack for P2P data transport and off-chain analytics – Henri Pihkala
Streamr is for streaming raw data feeds. Like IoT sensors, temperature. Creates a data stream economy.
Want to create a marketplace and make it like an “app store for data streams”



[p2p] – Self-sovereign BigchainDB data injection in smart contracts through the Jolocom Identity Gateway – Dimitri De Jonghe, Eugeniu Rusu
Decentralised data gateway for Ethereum
BigchainDB is a “planet grade database”.
A lot of our personal private data is in data silos owned by corporations.
Combination of private data + public claims.
If you know where your data is being stored, you could grant/revoke access.



[p2p] – PSS – Node-to-node communication over swarm
stores chunks across many nodes. Then nodes can retrieve from nodes. Has a routing algorithm to try and be more efficient.
PSS uses the same kind of logic, but for message passing instead of files.
Node addresses are generated as a long string of bits. To randomly split up the network. Nodes think of neighbours as being “close” by how similar their bits line up. Completely ignores the concept of geographical closeness. May not be geographically efficient, but is efficient with routing.
Messages are forwarded from node to node. Compares the address to its respective peers, then forwards on to a node in the correct direction (closer number of bits).
Messages are cached on the node, so it knows if it has seen it before.
To help mask metadata of who was the intended recipient, as you get closer to the correct node, forward it on to additional nodes. Final node passes it on so you don’t know it was the last one.
Using the Whisper encryption and message envelope.
Uses the same Whisper message padding to hide metadata



[p2p] – Workplace messaging using PSS – Shane Howley, Carl Youngblood
Company name is mainframe (that will be fun to try and find any documentation online).
A fully decentralised messaging system. It is alike a decentralised Slack with privacy.
Can be used with a company and also secure cross organisation communication.
Help guard against corporate espionage. Helps protect against accidental leakage.
Mailboxing service.
Swarm node. Exposes a GraphQL API. (there is some pretty cool tech under the covers)


Add contacts via their public key. Then can start sending messages



Designing IoT Frameworks Using Ethereum – Shuang Liang, John Gerryts
, lightweight pub/sub message transport. Designed for sensors with low bandwidth channels
Wanted to combine with Etherem to get trust and global identity.
MQTT-Trusted combines them.


uDapp (miro dap)
Sounds like it is a standard Dapp? Files stored on IPFS, etc. Think the only difference is saying that the uDapp device is running on a IoT device like a car.
Use Geth client in light sync mode. Then use MQTTT for messaging (instead of Whisper)
Wrote a Nodejs library for SoC to access HSM (hardware security module)



AKASHA: Unveiling The Next Experiment
to make a decentralised social network that isn’t centralised (like Facebook, who own your data).
Collective memory and freedom of expression back into the hands of people
Uses Ethereum & IPFS


Every user needs to burn a small amount of mana to interact with the network.
You lock your AETH token for a small period of time, get mana. Burn mana to do things. Mana regens over time.


But then they read from Vitalik that most tokens are useless. They need sinks, not just flows. So now they are re-evaluating everything. Trying to figure out what “Token 2.0” is

Devcon 3 report: Day 3 – Dapp development

Other reports:

Sessions you should focus on and watch:

  • uPort (will help solve end user access of Dapps)
  • metamascara (metamask javascript client)
  • Mist browser moon project (more secure Dapp engine)
  • DappHub. Check out the DSAuth contract to handle Auth in a standard way.
  • Real world smart contract development lessons

There were a bunch of sessions on Oracles today. Make sure you check out Microsoft’s version of it as well 😉 “Enterprise smart contracts”

Intro to Solidity (2017 edition) – Hudson Jameson slides here.
Solidity is like Javascript. Code is compiled to the EVM (Ethereum Virtual Machine)
Once deployed to EVM is completely isolated and cannot reach outside the EVM.
Easy to write contracts, hard to make sure they are secute
ERC20 is a standard to help with contract interoperability for tokens.
There is a `payable` modifier in solidity to mark that the function can take in Ether (helps protect against accidental ETH sending)
`constant` function modifier is being replaced with `view` and `pure` to be more specific.

Metamask + remix + etherscan demo
Metamask is a plugin that acts as a bridge between browser and Ethereum network
is a solidity IDE, helps with debugging and static analysis
is a blockchain explorer
In the demo he opened up Remix, pasted in a contract, clicked deploy, Metamask opened and he confirmed the transaction, contract got mined/deployed, and could see it on Ethercan.
On Etherscan can see details about the contract, if it has any ETH in it. Can submit the source code to Etherscan, for transparency purposes of verifying what a contract does.
In Remix, can use the IDE to invoke methods on the contract. In Etherscan can see the data values updated in the contract.

IDEs you can use: Remix, Visual Studio, Visual Studio Code (see my blog post on setting that up), Vim, etc.
: Truffle, Ethereum Package Management, solgraph,
Solgraph takes your function code and shows you a graph of all the potential function calls and the dependencies, to see where the security boundaries are.

Flexibility in Solidity – Dr. Christian Reitwiessner
Language design is a game of balances. Functionality / complexity / safety.
The path for Solidity, the initial goal was to create a usable high level language as fast as possible. They succeeded… but now it is time to evolve it and make changes to help make it safer.
Structs can now be passed into Solidity functions!! (This has been a massive pain point for me! Happy to see this)
And you can return an array of structs!!

Can use require() and assert() to make your function safer.
For formal verification can use SMTLib2 / Z3. Can prove certain things about a function. Like variables will be in certain ranges, there is a divide by 0, stuck in an infinite for loop.
Can enable it in your .sol by adding `pragma experimental SMTChecker;` If an assertion fails, it will tell you why it failed with sample data.
If you have a simple function that takes in (int a, int b) and do a+b you could get an overflow. Will show you the issue at compile time. So you could put a require at the front to have an upper limit on a and b.

Asserts in your code are fine. Asserts should never be reached. If it is reachable then that is a problem. Asserts help the verifier to make sure it never happens and your function works as expected.

Mist: towards a decentralized, secure architecture – Everton Fraga, Victor Maia
Mist is there to host the Web3 project. Which is the vision of having a peer to peer decentralised internet with a Blockchain backend.
At Devcon 1 there was the first version of the Mist Wallet. Could to transfer, execute transavtions. But was waay too complicated for average user.
Devcon 2, released the Mist browser beta. Works for enthusiast user, full web power for smart contracts and Dapps. But requiring that the entire blockchain gets downloaded and synced first is a bit of a hurdle.
Ethereum wallet & mist have been downloaded 2.6 millilon times
Held a Mist summit in 2017 to talk about and decide on the future of Mist


Recently has focused on hardened security. Did an extensive audit by Cure53. They found 22 issues of varying security levels. From that they improved their test suite, and then fixed.
Have Ethereum bounty program to help encourage community to track down more.
Now has swarm integration to upload files to swarm. Bzz://aacfee00123412…
Has DNS integration so can also do bzz://
Has ENS support for wallets.
To help with syncing times, supports Geth light client. (currently uses v1 light client protocol, v2 coming soon).
Built in Remix IDE. Can debug the steps that a transaction did.
Solo network, can use Geth with –dev flag to run an empty blockchain on your own node for testing.
Added a Windows installer. (Maybe I should talk with them about getting it onto the Windows Store)
Account management, standalone transaction signer. Means now you can sign locally, and then submit to Infura, or
switch between nodes.
If the accounts are managed by mist, means they now support different ethereum clients.
Did a major refactor recently, to help make it easier to add new features.
For Dapp developers, isolating local storage between networks. Different scopes to work with.
Sync jumpstart. Just get current headers, then sync the rest in the background.

Futures: better integration with remix, improve private net integration, puppeth kickstarts.
Could there be a Dapp trust level? Should dapps have access to HTTP (can be used for unencrypted tracking)?


Ethereum wallet.
Previously it was the best way to do your ethereum development (for deploying contracts), but now have Remix. So deprecating advanced features like contract creation. Creating a new Wallet.sol contract.

Q: Where is the decentralised web?
Still using centralised servers for Dapps. With centralised APIs, etc.
Mist relies on a lot of software stacks above and below it. How can you ensure that it is secure when we are dealing with keys that control real money.


Need to worry about javascript libraries you use. If you import them, they may modify the global space and add in trackers or modify web3 connection.
Web3.js has a lot of dependencies (showed a slide of the 60+ .js dependencies)
The web isn’t ready for crypto 😦
we don’t need a browser. We need a new app to access the decentralised web.

Announcing the moon project.


Gave a live demoFunctions are pure. UI layouts are on IPFS. Can build up a new UI by importing those different Uis and composing them. dapps are stored on IPFS for future retrival. Can take the code and create your own spinoffs. The decentralised web is mixable.

It looks promising
Video of demo at 1:13:00

Dapp Development using Remix, Mist, and Geth – Yann Levreau, Rob Stupay
Remix is a solidity editor, integrated runtime environment with web3, and code analysis.
Can go to the compile tab and see compiler errors.
Can go to the run tab and execute functions on the contract
Does some static analysis. Can warn if gas requirements are too high.
Just talked about generic features of Remix.
It is colour themable..

DappHubb – Andy Milenius

DappHub is a self organizing network of logicians, researches, designers and developers.
Inspired by the Unix design philosophy for small reusable components. Want to make lots of free composable tools for Ethereum.
They are sick of Dapps that are using useless tokens. We want to free the Dapps of useless tokens.
People could take the Dapp, fork it, and remove the useless tokens
Created an ergonomic Ethereum toolchain.
They used it with MakerDAO
Share their tools using the Nix package manager
of the basic components is seth, which is an Ethereum swiss army knife. Make it easier to interact with blockchain instead of using web3. means you can use seth and make it composable on the command line with other tools.


Dapp tool for quick builds, powerful tests, easy deployments. Stack tracing.


Provable standard library for Dapp development.
Brings the same philosophy across to the smart contracts. Small reusable provable components.
There are 2 concepts: boxes & mixins. Can mixin Auth and Math and then use throughout the app (to bring in features).
Boxes are prebuilt components that have been put into a usable Dapp that you can just use off the shelf


DSAuth mixin, abstracts your Auth logic away from your Dapp business logic. Provides a DSAuthority property. Gives a canCall function, acts as a guard on the function, based on any arbitrary business logic, e.g. whitelist, timeboxed, role based, voter veto.

DSToken Box, is of type DSAuth.
It is a token that has 4 functions: stop, start, mint, burn.
Thinks Tokens should just be tokens. Just a DB of who owns them. Move the auth out from the business logic by using DSAuth


A traditional token is complex

An easier way is to think of them as single reusable components.

Real-World Smart Contract Development Lessons – Raine Revere
Suggestions for Dapp development.
Central logging: If you have a multi contract system, use a central logging contract to make it easier to track.


Modular libraries: Deploy code once, that other contracts can use over and over.
Think about having a data sctruct that can be reused. Then when you are calling other libraries you can just pass in the pointer to the data contract that has the struct, so it can read it easier.


Arbitration: use the blockchain as a court system / arbitrator. Assume people will act in their best interest cooperatively and the happy case most of the time off chain. Use the smart contract to execute and be the arbitrator.

User A uses the system and the counterparty does the right thing, execution is super simple.
User B uses it, has an issue. Raises a disupte, then does all the expensive logic and the bad party is punished by paying the costs.
Because the party behaving badly knows that they can be called out and will need to pay the costs, they are incentivised to just do the correct thing and everyone saves money.


Role analysis: who is interacting with the system
Buyer wants to buy, seller is putting up the assets, oracle is publishing the prices. Helps simplify code interactions


Context dependence
Send vs withdraw. Send is vulerable becaues the person you are sending it to could be doing something bad in the receiving code. But maybe you want to keep it simple. “it depends”. Think about the tradeoffs

MetaMask: Dissecting the fox – Aaron Davis, Frankie Pangilinan
~200k users
Team has grown from 4 to 10
Will support HD wallets.
Mustekala project. Ethereum on IPFS to help bridge the two

Dan came on stage dressed up as a T-Rex
V4 will have a new UI, token management and responsive layout.


It used to be difficult to be able to get Metamask working in your website. Was a bunch of JS to check Web3 context, etc.

Now much easier, only 4 lines (I missed taking slide photo).

But it will also allow you to not need to have the Metamask browser plugin installed. It will now do it in JS and redirect you to to use your wallet.


Web3.js 1.0 – Fabian Vogelsteller
Web3.js is middleware to save you converting values and transaction calls between JS and a node. Handles ABI encoding
EVM only knows bytecode. Everything that goes into it needs to be converted.
1.0 is a serious refactor.

It now has promises.
Blockchains have a weird async operation where you need to wait until it mines and is a few confirmations deep. Can use Web3.js PromiEvent to say when to move on once you’ve received enough confirmations.
Subscriptions based on WebSocket or IPC socket, instead of polling.


Web3.eth.accounts can now create, decrypt, sign
Web3.bzz allows you to interact with swarm to download and upload.
Web3.shh communicate on whipser.
Web3.utils.soliditySha3 allows you to make sure you hash the same way solidity does (important because Ethereum uses an earlier variant of Sha3)

Missing Links in the Ethereum Stack – Jack Peterson
Is the lead developer on Augur
Wants to look at Ethereum tooling, call out what he thinks needs improving, and is offering bounties to incentivise it.
Ethereum is a young ecosystem, is missing tools you may be used to in general software engineering. It feels like it is at the old early stages of computer engineering.
Lack of incentive to build good tools. Prefer to just go do another token sale.

Wish list:
We need a better debugger. Remix is too much, it is a full IDE, awkward for large projects, doesn’t integrate with other tooling.
He wants to pull the remix debugger out to be portable (I agree, could bring it in as a VS Code extension)
Put a bounty of 2,000 REP for this

Good code vs safe code. Need to think about how other safety critical software works. They do it via fewer features, less abstractions.
2nd bounty of 1,250 REP for a super simple solidity. That restricts things right down to not include inheritance, recursion, etc.
1,250 REP bounty to enable return values in transactions.

EthJS – Precision Ethereum Javascript Architecture for dApps – Nick Dodson
Ethereum in 2017 are a bunch of variants web3.js, EthereumJS, parity.js
He got frustrated with Web3.js and wrote ethJS
It follows Ethereum RPC specifications, and follows an identical provider model to web3.js
Metamask & mist are supported.
It is very similar, just with his opinionated improvements 🙂
ethjs-deploy, configurable contract deployment facility


Panel: Development Frameworks
On the panel is:
Creator of Embark
Jack Peterson, Augur
Andy, DappHub
Nick Dodson, Consensus, boardroom, Weifund, EthJS
Yann, Remix
Piper Merrium, python tooling ecosystem. Web3Py, populous, Ethereum Package management.

When they got started there were no tools, so they created their own tools.
DappHub: we wanted to solve problems in reusable ways
Nick Dodson: anger and confusion and questioning his own identity, spurred him on to create his own dev tools. Got frustrated with Web3 and wanted to do his own thing.
Lots of talk around how we lack a good package manager right now (EthPM later). We badly need one.
Nick: Don’t waste your time creating another bullshit token ICO that will have a 99% chance of failing. Go and help out with tooling and help the long term health of the eco system. *cheers*

Uport – Usable Key Management for Multiple Identities Across Multiple Chains
“we have built Ethereum’s user platform”
Can handle account management and login. Onboarding new users without Ether. KYC scnarios, etc


All Ethereum app accounts are in one easy place to manage.
Store credentials and badges
Create a completeuser profile store.
Mobile factor auth and signatures


Just because you lose your phone doesn’t mean you should lose access to everything.
Your identity is handled by a simple contract called a proxy.
The private keys are kept on the mobile device.
Can do things like social recovery, with other recovery mechanisms coming in future


Started off as just on a single blockchain. But realised there are many networks. So now supports multiple networks

uPort handles account management for older web 2.0 and newer web 3.0
uPort connect library that uses web3 library and sends messages to your phone to authenticate.
Identity is always handled by the end user.


Users want to use apps, not worry about networks and gas.
Guide them through account creation and joining correct network. Solving gas issue by making all transactions going through uPort contract which pays the gas on their behalf?


Developers want to issue badges and other credentials to users. Giving some form of attestation
If you achieve a certain certificate, are over 18, just personal things that you can attest. Can keep it off chain.
There are enough companies out there that are doing KYC. Integrating in KYC providers. User shares their KYC badge.
uPort credentials is generalisable as user centric data that forms the basis for reputation systems.
If using an decentralised AirBnB want to track reputation


Demo video at

Data is the Missing Link: Enterprise grade oracles
Thompson Reuteur
They knew that they could be disrupted with Blockchain. Realised they could become a trusted oracle, as people trust them currently.

Decided to focus on the high value, low volume space.
Focusing on things like share prices, FX rates.
Corda & Ethereum. Currently only on testnets. Will be free, but need to agree to T&Cs.
Show an example of using oracles to pump in prices for ERC20 tokens, and have people buy/selling
Had to architect things differently, to keep their content they license from other parties within the usage agreements.
Looking to expand data coverage. Electricity & natural gas prices requested.
Looking to expand to KYC as a service, for governance & transparency to unregulated markets. So they can help token sales for example.


Secure Decentralized Oracles: Applying Intel SGX and TownCrier to external data, payments and off-chain computation – Sergey Nazarov
Smart contracts are unable to connect with external data.
Blockchain middleware takes external data and provides them as inputs into the contract.
Want to connect smart contracts to widely accepted bank payments systems, so can pay in local currencies.
Connect smart contracts from different networks so they can interact.
Centralised oracles are a point of failure. One node as a trigger

Town crier. Is open source.
Run it as a decentralised oracle network.
Use trusted hardware (like intel SGX)


Intel SGX probably returns the execution outputs. Here the executed software is the town crier software.


Scalable Onchain Verification for Authenticated Data Feeds and Offchain Computations – Thomas Bertani

Oracilze wants to help be the general provider of data to smart contracts.
Help bring in data feeds and have multiple parties give authenticity proofs.
Is a more general Oracle offering over Town Crier which is for scoped use cases. Allows chains of trust, and bring back more than one proof of the claim.


Snopes meets Mechanical Turk on a Blockchain: Reality Keys, On-chain Truth Verification and Subjectivocracy – Edmund Edgar
What is truth? It is a big issue at the moment with US politics embracing “alternative facts”.
Any paid advertise can push claims onto your screen. If you are faced with a claim, then you could spend time and effort trying to figure out the validity of a claim. But it is impossible to verify the constant barrage of bullshit so you just let it through. Get hit with enough stories again and again, start to take it as truth.

Created “reality check” Dapp. Is a mechanical turk for truth.
People who give correct answers get rewarded, incorrect get penalised. When answering you put down a deposit, returned if correct, taken if incorrect.
But what happens if someone gives incorrect biased answers, but puts down a MASSIVE deposit and makes it difficult for people to correct them. Can use an arbitrator to resolve it.


Mind the Gap: Application-driven evaluation of Smart Contract languages – Andrew Miller

Research papers. Compared the difficulty to develop apps on Bitcoin scripting vs Ethereum contracts





Devcon 3 report: Day 2

Other reports:

Today’s sessions I suggest you watch are: “The future of token contracts” and “Raiden network” as you can start using µRaiden now in your apps (and there is a cool demo of them using payment channels to control a robot)

Developers, Developers, Developers – Peter Szilagyi 
Ethereum is currently a developer tool written by developers. Isn’t easy to get started.
Usually developers start doing Solidity in a browser
Then migrate to using a local dev framework work VS Code + Truffle
Then deploy to a test net (but test net has a bunch of issues with stability and spam attacks)
So spin up your own network which is “difficult” (Or you could just deploy a private testnet on Azure 😛 )
They have built Puppeth to help make private networks locally.

Step 1. Genesis file
Genesis file is difficult to hand code.
With puppeth you can run the CLI wizard to generate it for you. Answer 5 questions, network name, consensus algorithm (PoW/PoA), etc.

Step 2. Config Ethstats
Use puppeth to deploy your own Eth server, and have it set the config files

Step 3. Boot the network
Deploy a bootnode to a new server using puppeth.

Step 4. Add some miners
Again, just use Puppeth to add a new network component, miner.


Step 5. Block explorer
Currently no open source block explorer that supports Geth, but there is one that uses Parity.
Use Puppeth to add an explorer to a new server.

Step 6. Give someone a wallet
Deploy a new network component, wallet. Deploys MyEtherWallet to your network. Configures it to have the web UI default to your network.

Step 7. Faucet
Deploy a new network component, faucet. Deploy it again to the same web server.
Configure how much ETH it gives out, per X minutes. e.g. 1ETH every 15mins.

Step 8. Allow external people to access
Deploy a network component, dashboard.
Select everything you want on the dashboard (faucet, wallet, ethstats, etc.)
Select to make it public
Gives a page on how to connect a Geth or Parity node, android apps, etc.

Walleth deep dive – Marcus Ligi
He likes Android. There wasn’t a wallet that he liked. So he decided to make is own.
Spent first 5 mins explaining why he put it on Android and not iOS. Can link a Tezor hardware wallet. You can select day/night theme.

Status: Ethereum at the edges of the Network – Jarrad Hope
Status is a hybrid mobile messenger and dapp browser.
Decentralisation matters. In Catalonia during the vote, they put the storage on IPFS, but there was a main centralised HTTP website for the average user to access, which was blocked. So people needed to go download TOR to access.


Status tries to help 1st time users with nice welcome screens and walk throughs in the app.
Try to stay out of the way, don’t get users to backup their key phrase, until it actually has value in it. At which point they explain to the user what to do and why.
To help users secure it, are releasing an open source standard for a hardware wallet. Java card based. Can sign, etc.

Have a discover protocol, to help sort through their contacts. Uses stats like how much they have interacted or chatted with a contact or Dapp to help build up it’s reputation, to protect against phishing. By building webs of trust. Users Whisper for messaging transport. An issue with whisper is that both parties need to be online. If one is offline the message just goes nowhere. Have a status message box where users can select where to cache messages.


Are releasing desktop app version on MacOS & Windows.
Their next steps are to work on optimisations, security audit, identity, etc.

Evolving devp2p – Felix Lange
Devp2p provides a lightweight abstraction layer for ethereum protocols. Covers node discovery, transport, application layer.
If you have a node that wants to join the network, it connects to the DHT to do discovery. Can see other nodes that have registered on there by their enode://. Then your node tries to do a TCP connection to one of the listed nodes.
They do a protocol handshake to check shared capabilities. Then check both are using same network id & genesis block. Chatty, requires lots of round trips. Network communication upgrades are tied to hardforks.

In the new version they want to achieve 2 things
Find nodes more efficiently, know more about nodes before attempting to connect.
In the DHT replace enode:// with an Ethereum Node Record which has location and capabilities.
Once you can put capabilities into ENR, then can experiment with other transports like IPFS/libp2p.
Want to add a requirement of endpoint proofs, to reduce dead/spam nodes listed in the DHT.

EVM-C: Portable API for Ethereum Virtual Machines – Pawel Bylica
There is the EVM, but there is a EVM API over the top of that that you interact with.
ECM-C is an API written in C to interact with it.
Wrote it in C as it can be ported to many platforms.
Allow you to switch EVM implementation at run time (e.g. v1 or v1.5)
Could allow run time smarts, like having a generic EVM that does JIT for contracts that are run infrequently. And an EVM that compiles bytecode into native code for faster execution, more upfront cost, but useful for frequently used contracts.
Point is to take the API calls and implement them, to make it easy to experiment with different EVMs


The EVM: Cleaner, Meaner, and Closer to the Metal- Dr. Greg Colvin
Works on possible successors to the EVM to help with performance.
Uses some standard benchmarks to check performance, around rc5 encryption, ecmul elliptic curve multiplication, and base EVM ops like add, sub, mul, div, exp. Just to give a base level to work from for each implementation.


What is causing the interpreters from reaching the native speed of the C++ implementation?
Interpretation, 256 bit registers. Unconstrained control flow.

EVM 1.5 restricts & extends current EVM. Provides opcodes for native scalar & SIMD vector types. Restricts unconstrained jumps which are hard to predict.
EVM 2.0 provides opcodes for structured control flow. More opcodes for scalar & SIMD. Validates control flow, type safety.
EVM 1.5 & 2.0 should be compatible. Can be transpiled between the 2 of them in linear time. Transpilers could live on the blockchain.

PANEL: Evolving the EVM


Talk about 64bit, 256bit, register sizes. Do pre-compiles help.
Academic arguments, talk was disjointed.
Transpiling is good/bad. Jitting will never be useful, yes it will.

Ethereum Security – Martin Swende
Security lead for Ethereum Foundation


Were lots of DoS attacks, testnet attacks, etc.
But by analysing the attacks after the fact they can learn from it.
Have added monitoring nodes to the network which graph stats. Through that found there were some inefficiencies around TX, which they have improved by 20-30x

Have put debugging features into the EVMs, so they can dump an opcode by opcode execution from them all, to confirm they are all implemented the same. To prevent consensus issues.
Created a transaction inspector, that allows them to see the memory contents of the EVM as they are executing. Helps to repro and analyse how attacks work. Allowing them to create fixes.

Started using fuzzing to randomly generate test cases. Execute across all EVMs, confirm with the dumps that all the clients are the same.
Clients are more tested now than ever before in history. Millions of evmlab/testeth-fuzz tests, billions of libfuzzer tests

Swarm Development Update

<warning, I get ranty about Swarm, my same arguments as last year. At bottom I add links to a comparison>

Swarm is a distributed file system. Takes a file, splits into 4k chunks, distributes over the nodes.
Swap is the incentive protocol.
Have released a PoC. Shows that the basic idea works, but it is slow. Frequent issues with trying to retrieve files.

Same question I had last year. We already have IFPS which has a solid tech, lots of mindshare. Why not just use IPFS tech, get the bonus networking effects of utilising IFPS servers for more chance of a file being available. Swarm team can just focus on the SWAP incentive protocol instead.

PSS is a message passing protocol. Messages are encrypted. The recipient can decrypt.
Is very similar to Whisper. In fact it uses Whisper under the covers. I asked the teams after why the duplication of Whisper & PSS. They said Whisper is like email, PSS is like instant messaging. Different speeds and guarantees. 

Built a FUSE extension to sync a filesystem directory to the cloud and to another device
They built an encryption system on top, encrypts the data and the merkle tree.
Swarm network simulator, to test what happens when nodes come on/offline. Consume without giving, bad behaviour, etc.
Upcoming swarm features: new syncing protocol. Complete rewrite of network layer. Are all breaking changes so everything will be wiped. Light swarm node. Extensible incentive system (swap, swear, swindle)


<<rant incoming>>

“people are using Github which is centralised. We want a plugin for swarm so it can host a decentralised git”
IPFS did this years ago.

“sync a folder / FUSE module”
IPFS had this years ago?

Swarm team seems to want to just build/rebuild their own stuff instead of just utilising what is out there. What is the reason behind all this?
IPFS can even read Ethereum blocks with the libp2p extensions

<<Rant update>>

Later I was forwarded this Swarm/IPFS comparison writeup done by the author of Swarm

Was a good write up. The swarm author very was fair.
Seems there is 90% overlap. Just organisational mismatch.

I do like the proposed integration points for the future:
· Layer the swarm incentives over IPFS, or make it simpler and compatible.
· Mounting IPFS over the transport layer (RLPx) of devp2p

Having network compatibility massively increases reach 🙂 I hope that Swarm does implement some integration.

Scalable Responsive Đapps with Swarm and ENS – Daniel Nagy
Dapps. Large parts of the business logic are done on the client side.
Web based / mobile apps / IoT, front ends. With a backend of ETH node (or light client), swarm for files, whisper for node to node communication.

Consumers spend ETH or tokens. Have a high churn rate, have limited resources.
Suppliers earn credits, low churn, high availability, more resources.

Dapps are limited by Blockchain transaction speed. Need to pay to submit state changes.
Limited to how much work an individual node can do on behalf of a Dapp. Can’t have all clients talking to same node.

For storage, keep data in swarm. Put the root hash in ENS.
Transaction bottleneck could be overcome with Raiden style updates to ENS.
Broadcast bottleneck, use PSS with pub/sub

Can combine these technologies to improve the perceived responsiveness of your Dapp.
If people are in a chat room, use message broadcasting to keep them live up to date. Then use the Blockchain for the eventual consistency for people who come and load the page later.
Could use root hash of all the chats sent, which are saved on swarm. Do aggregation on the client side, rather than complicated updates.
Can roll out new versions by pushing a new version of Dapp files to Swarm/IFPS. Then update ENS with new root hash.

The Future of Token Contracts: MiniMe, Governance, LiquidPledging & ERC223 – Jordi Baylina
MiniMe contract. Is an ERC20 token. Has been used by distroc0x, giveth, swarm city.
It tracks the token distribution history on the Blockchain. Means that the token is forkable. Means you can create a new token whose distribution is the same as the cloned token. After the fork, each token is independent of each other.
Example use case means you could take an existing token, clone it, have the cloned tokens as burnable votes whose distribution is the same as the original token holders. They can now vote.
Instead of voting, they could be discount coupons.
Means that you could upgrade tokens by cloning with a new code base, and deprecating the last token contract.


Future of tokens: ERC20 is a little broken. Look towards ERC223. Only pending issue is backward compatibility.
EIP672 is a proposal to look up capabilities of a contract. Means if you had an ERC223 contract, it may not support some ERC20 functions, but if you look up the capabilities, you can see there is a proxy contract that can handle that functionality.

MiniMe+ERc223 = Yoga Token.
He wants it to be the new Standard Ethereum Token. As it has the new ERC features, plus the MiniMe features of cloning.

Liquid Pledging.
It is a combination of Liquid democracy and fund management. You can manage your tokens, and someone else’s tokens on their behalf. To handle voting.


Designing Future-proof Smart Contract Systems – Jorge Izquierdo
Aragon is a platform for Decentralised orgs. Allows extendibility via third party on-chain modules.
How to ensure that contracts are future proof. Dumb contracts are the best. EVM is expensive, optimise for gas savings. Contracts need to be upgraded eventually.
The goal is cheap, upgradable, and very simple contracts.
Upgrades need to think about governance. Not just 1 entity is in charge, let people vote on the upgrade.

Solidity libraries are one approach, but they are linked in at compile time, can’t upgrade.
Instead you can link to a proxy library that would forward onto real library. But problem was you couldn’t modify ABI to add new functionality.

Delegate Proxy. EIP211.
Static forwarders are another way to deploy cheap “clone contracts”.
Solidity forwarders another.
Upgradeable Proxies (from Nick Johnson’s upgradeable.sol)
They are using AragonOS. Has a tiny kernel contract, with upgradeable mini business logic contracts.

Panel: USCC – The Underhanded Solidity Coding Contest
Ran a competition to write smart contracts that look innocent but were malicious. The theme was token sales.
One entry used a feature where you can send a header without triggering contract execution? Used it to exploit the token sale contract he wrote, where the token cost was based on when
2nd entry Suicide bug. Crowd sale, the issuer gets 1ETH 1st week, 2ETH the 2nd week, 4ETh the 3rd week. So that they’ll get paid based on performance. But it is based off this.balance so if you figure out where a contract will be deployed. Send ETH there first and THEN deploy a contract, funky things can happen.
3rd entry Exploiting something in the ABI, could make the parameter one value type, then pass in a different type. Use that value in a loop for dynamic arrays. It isn’t exploitable using normal tools, needed to generate your own ABI to pass the data in.

If you see this.balance, it is a red flag. May not be what you expect it to be.
Random numbers are a point of failure.
External calls are another security edge.
Don’t build giant inheritance models, makes it more complex to reason about.
Think about miner front running.
Maybe we need analysis tools over the bytecode
Check the Consensys best practices guide

Hardening Smart Contracts with Hardware Security – Nicolas Bacca
Maybe an incorrect title. The session was about secure hardware devices, and the low level details of how they work on the device CPUs for trusted execution.

Secure hardware is an isolated environment for secrets and security sensitive operations. Proof of execution on a hardware and of its health.
Unfortunately current hardware microcontrollers have NDAs or binary blobs which aren’t auditable. No real open hardware yet. But are getting more open.
Spent time going through many slides showing how hardware security devices work. With isolated data, and on chip app domains that can only access their own secrets. Covering how ARM does it, SGX, etc. Too technical to write here.


Raiden network
Scalability solution for Ethereum. HTTP RESTful API.
Raiden is a separate process that communicates with an Ethereum node over RPC.
Currently only supports ERC20 token transfers.

Step 1 connect to a raiden network.
Tell it how many tokens it is allowed to use. It will handle the channel management automatically. But can handle manually if you need. Can then deposit more tokens, or close the channel.

Step 2 can make transfers
Just do a POST to make a transfer. Need to include your own identifier, to help both parties know what this payment was for.

Step 3 react to events happening on Raiden network
Transfer received, transfer sent, transfer failed

µRaiden (Micro Raiden)

seems µRaiden is a simpler cut down version of Raiden which you can start using now for your own use cases.

Example of a token fuelled robot.
Set up a few channels, one for each direction the robot could move (forward, back, left right).
When the payments go through, the robot would move. Robot could consume the tokens based on distance moved.
When finished closed the channel and got the payment on the blockchain.
Video of the robot from 3:57:40


Towards a Permanent ENS Registrar – Nick Johnson
168,500ETH deposited.
8,500ETH lost through unrevealed bids and mistakes (0.3%).
1.4% of the owners own 50% of the names
One account own 17,500 ENS domains
Broad adoption across the ecosystem. In Metamask, My Ether wallet, etc.
Suggestion that instead of using ENS directly, users could go through a proxy contract that will filter out a blacklist of known phishing accounts.
Will be using DNSSEC so that people who own domains can own those domains on ENS?

Devcon 3 report: Day 1 – core systems

Other reports:

The 2 talks to watch are: “Regulatory update and look ahead” (covering a security is) & Vitalik’s talk at the end of the day on scaling/sharding & Ethereum 2.0.

Format for the week will be:
Day 1 is core tech
Day 2 is research
Day 3 is Dapps
Day 4 is ?

Ethereum team introduction

Vitalik – Founder
We are working on research into what the future of Ethereum will look like, to support the future of Dapps.
Working on Casper, scalability, etc.

Martin Swende – Security Lead
Is across all the projects, to try and keep across security issues. Especially the network protocol.

Peter Szilagyi – Geth team lead
Since Shanghai Devcon 2 last year.
Released mobile library.
Made a new P2P protocol for private networks
Released a light client version
Added Proof of Authority to the plugable consensus, and it is being used by one of the testnets
Focusing a lot on performance bottlenecks.
Reduced DB size by 50%, syncing time by 60%

Zsolt – Geth, Light Client dev
Made lots of progress on light client (syncing, log searching, p2p discovery, etc)
Looking forward to the production release

Dr. Christian Reitwiessner – C++ client / Solidity team lead
Looking to get C++ client working again
Snapshot syncing. Removing race condition bugs.
Improvements to EVM, v1.5
Working on ZK-Snarks

Yoichi Hirai – Formal verification Engineer.
Writes mathematical proofs
Followed the Metropolis changes, wrote test cases against the implementations.
Helping to prove Casper. Will talk further on this later today

Alex Beregszaszi – solidity, eWasm, ethereumJS
Solidity changes so far: Function types, contract metadata, new compiler interface
Solidity futures: new language, new formal verification checker (snt checker?)
EthereumJS – support for Byzanthian fork. Important as other projects rely on it like Remix.

Yann Levreau – C++/Remix developer
Remix is a web based IDE.
Working on improving UI and backend code.

Piper Merriam – Python team lead
Established a spec for packaging smart contracts, and looking to get that implemented across the ecosystem
Responsible for a lot of the Python tooling. Working on bringing it’s quality up to par
Working on an alternative EVM called pyEVM
Looking to bring it online as a new light client

Viktor Tron – Swarm team lead
Swarm has grown beyond the intial scope of a flie store for Ethereum, now covers high bandwidth communication
Tomorrow session will be the main session on it
Developed a network simulation to check things like high node churn.
Main initial release will be around cloud storage to sync between their devices.
3rd party application uses, like live audio streaming.
Working on privacy and censorship resistance communication.

Vlad Gluhovsky – Whisper lead
Whisper is meant to deliver data. Want to make sure no data or metadata is leaked. Tomorrow will talk about this

Everton Fraga – Mist team lead
Been working on bonding some other projects into the Mist browser.
Working on making it more scalable. More info in Friday’s session.

Fabian Vogelsteller – Mist, web3.js
Will do a session later in the week on the 1.0 refactor.
Proposed a new ERC 725 – around identity.

Regulatory Update and look ahead – Jerry Britto
HIGHLY suggest you watch this session if you plan an ICO or any serious Blockchain Dapp

Coin Centre seek to educate policy makers
Year in review:

  • Uniform Law Commission – supplements the money transfer license. Helped define what “control” means, to help be clearer who needs a license. Only if the company “controls” the currency, helps with some exemptions. Defines who is an intermediary and need regulation
  • Helped deliver a bill into congress around tax – examples like using ether to pay for a smart contract execution is technically taxable
    any transaction below $600 you don’t need to track.
  • FCC – talked about securities and tokens.
  • Potential terrorist use of cryptocurrencies – put on a demo day to help educate members of congress. Conclusion at this point, it is a serious potential threat, but isn’t an issue at this moment.


Characterizing issues on the horizons:

  • Regulatory hotspots around securities regulation & AML (Anti money laundering)
  • AML law boils down to Is the token being used as a currency substitute. Is there a centralised issuer tho can also withdraw from circulation. If yes, they are an issuer. Otherwise they are an exchange (like Bitcoin/Ether)
  • Securities law boils down to: is the thing being sold as an investment. Is there a person upon who investors rely?
    No one person is relied on around gold. But a share/stock of Apple is a security, as you rely on the company.
  • Issuer vs. Network
    Money goes in, more goes oug -> Investment
    Money goes in, utility goes out -> Network



Super useful diagram of what is a security.
Coin Center is helping to suggest that FCC should focus on investments controlled by a single issuer, to help protect people, but leave the rest of the ecosystem open.

Ethereum in 25 minutes – Vitalik


In 2013 blockchains are useful for ‘stuff’. Not just money but for thigns like Asset issuance, crowdfunding, domain registration, IoT, voting, etc. More than just transferring BTC
Original Blockchains were single function.
Why not make a protocol that works like a programmable smart phone. So that a single blockchain can run multiple use cases / apps. General purpose computation.
Smart contracts that could control digital assets. When to release assets to other people.
Also to program other business logic, like voting, ENS, etc.
Every transaction specifies a TO address. The code at that address executes. Code can send ETH to other contracts, read/write storage, call other contracts
Every full node on the blockchain execute all transactions.
Halting problem was an issue (e.g. infinite loops). So gas was implemented to help constrain it. Charge a transaction fee per computational step.
Logs are an append only data, not readable by contracts. 10x cheaper than storage. Up to 4 topics for bloom searching. Intended to allow efficient light client access to event records (things happened)
You don’t write in DVM bytecode, instead you code in Solidity, Viper, LLL, Bamboo.
The ABI describes the function calls available on a contract, so that clients can call into it.
Byzantium introduced some precompiled functions to verify: Ring signatures, ZK-SNARKS, RSA
Also added new functions like assert(), revert(), require()

Future directions for core Ethreum: Casper, Sharding, EVM & protocol upgrades.
Are still other things in broader ecosystem like Plasma, state channels.

Methods for deterministic parallelizing message processing – Martin Becze
started in ewasm. Plan was to build off web assembly instruction set, to add in metering.
Issue was that you had to run transactions sequentially, not concurrently.
Is a layer that sits between VM instruction set and consensus mechanisms.
For scalability, need to apply locality.
Right now all contracts exist in the same namespace. One way to impose locality could be that each contract has subcontracts that only it can access. Means the subcontracts could all be executed in parallel as they can’t effect others directly. Problems with nested contracts. Inflexible, inefficient.
Next approach Try to build up a graph of how contracts interact, then use that to define shard boundaries. Can create a bigraph from this.
Got very very technical from here on, about different messaging strategies to try and break tings up and be more async.

Practical applications of off-chain computation in the light Client ecosystem – Zsolt Felfoldi
Do computation, do a validation process to verify it.
One application is for event filtering for history searching. If we shard or do state channels, there is going to be a hierarchy of data that needs to be searched.
Currently uses bloom filters. But in a bloom filter you’d need to filter through 4million+ blocks reading all headers (currently 2.2GB). Light servers can search and present it to light clients, but clients need a way to validate it. Bloom trie root hashes can be interactively validated on chain.
Users want to observe multiple subchains (when sharding) and get notified by new events using a complex filtering criteria. Light clients can hire a full node (light server) to validate and certify a subchain. Client specific event filtering can be done server side.
Chain filters. Deterministic operations on an input chain.
Observer chain: belongs to a single node, processes multiple observed chains. Checks the current best heads of observed chains.
Building a filter hierarchy. Observers can build on top of other observed chains. Can have base ones filtering out bulk of stuff, and then further layers refine it further.
Build up a market of services for light clients.


Parity: A Light client for heavy chains – Robert Habermeier

Ethereum clients currently can be defined broadly as:
Full nodes – they check and verify everything. But storage and computation requirements are heavy.
Light client – verify block headers, but not checking transactions. So checking that mining consensus is working.
Thin client – isn’t checking consensus, relies on others to do it for them.

Light clients check validity of headers. Does not check validity of state transitions. Might lead to some targeted attacks, attacks wouldn’t work on full network which is validated, but targeted to a single client.
Protocol goals: minimize roundtrips and bandwidth required. Full nodes are serving data to light clients, need to think how to present denial of service
Put multiple requests into the same request package (I need block X and account Y).
Can use state proofs to get a subset of a state tree.
Metering system, using request credits. Each node can come up with their own pricing. Different requests have different costs.
The average person won’t run a full node, but we need them to support the network of light clients. Needs an incentive system.
Pub/Sub for events. Reduces polling and excess work.
Warp sync: Users usually don’t care about really ancient data. Can just jump to more recent blocks. Ancient block download can happen later (e.g. when on wifi).
RPC pitfalls: on light clients some RPC calls don’t work.
Eth_getLogs can be very expensive if you are checking all history of everything. If just watching the head for events, is much cheaper.
Eth_get*ByHash the hash of the block has no info about the actual block number. So will need to search through the history and maybe forks or uncles. Lots of work to search
Eth_estimateGas need to check state proofs of multiple executions. Lots of computation to guess.
Lightclient+whisper+ecosystem. Light clients are viable for mobile devices (on wifi) whisper makes a powerful tool for messaging and medium latency state channels. Projects like status are already using this and showing how this can be done.
Looking at compiling light client into Web Assembly. Could embed into a web page.


Verifying Casper – Yoichi Hirai
Casper is the planned Ethereum Proof of Stake protocol.
There will be a capser contract on each (divergent) fork. Validators deposit ETH, when they do the right thing they get rewards, bad they lose ETH. Validators can vote for a block. Can’t double vote or they lose.
To avoid losing deposits, just need to be careful about what you sign. Will only really lose if you are doing bad things.
When a block has 2/3 votes from validators, then they are justified and later finalised.
Next 10 minutes is lots of mathematics diagrams. Track the ancestor blocks and votes and punish bad people who vote for divergent forks.

Sikorka: Proof of presence for Blockchain applications – Lefteris Karapetsas

Network of detectors that provide proof of presence. Different types of detecots exist. Contracts choose detectors depending on security requirements.
Users interact via a phone app.
Proving presence for bureaucratic reasons. AR games. Objects directly interacting with smart contracts (smart locks?)
Different detector types that the system can use, contracts select types based on security requirements.
One detector is the “Revealo temporal BLE tracker”. Provides accurate location, uses temporal keys to preserve privacy.
A super cheap detector could be a screen somewhere that generates a new QR code every 10 seconds that you can scan to show you were there.
There is a central Sikorka smart contract controller that indexes all the contracts. And a contract interface you can use to hook into the system.
Basic usage could just use your phones GPS (but can be spoofed).
More secure uses a detector. You interact with the contract to show you are near the detector.

Julia: IR (Intermediate Representation) for Ethereum Contracts – Alex Beregszasci
Why do we need an IR?
Complexity of auditing solidity contracts. Helpers & optimisations of Solidity. Porting Solidity to other VMs.
Auditing that the compiler did convert solidity into the correct bytecode is difficult. EVM bytecode is very cryptic to read.
Compiler pipelines usually go in 3 stages: parse/analyse, optimise, create bytecode.
But the solidity compiler only really does the 1st and 3rd. Smooshes it all together. Julia will sit in the middle to help support other functions.
Benefits are that more of the compiler can be moved out of C++ and written in Julia, for simpler reading.
Also means it is simpler to optimise code before generating bytecode.
Julia currently supports: typed variables, functions, switch statements, if, loops.
Will support output to EVM, EVM 1.5, ewasm, others (like outputting into JS or C for integrating into UI side)
Could get your own DSL to compile into Julia, which could then output into EVM bytecode.

Package management for smart contracts – piper merriam

Last year they got togther and proposed ERC190 smart contracg package spec
ERC190 deterministically create a package that is immutable.
Packages can include: sull source code, compiled assets, compiler info, ABI, address of deployed contracts, link reference info
Useful for public chains, but also for private chains.
Example of the simple inheritable contract.
The .json file of the package defines metadata, and a location of the .sol source on IPFS.
Your contract can have its own package definition, that has a dependency on another pacakge.
Package could not just store the .sol, could embedd the compiled bytecode, or just the deployed address so you can link to it.
Could use it in a wallet, import the package and it will give you the ABI that you can interact with.
Could combine it with ENS and have package indexes that list source of truth for contracts.

Programable incentives: An intro to cryptoeconomics – Karl Floersch
Blockchains have open access. Anyone can deploy a contract or send a transaction.
Trusted execution. All smart contracts and transactions will execute as defined.
Now we have programmable money.
Designing incentives. You can’t talk about blockchain consensus security without reasoning about economics.
So you can combine cryptography (hashing, signatures, etc) + economics (tokens, voting rights).
Want to use cryptoeconomics to enable good outcomes like trusted execution, and protect against censorship.


Example project: Market maker. A simple automated market maker contract.

  1. Design a mechanism
  2. Analyze incentives
  3. Make a website
  4. Observe behaviour
  5. iterate

Deploy a market maker contract with an initial deposit of ETH and tokens. Is an automated exchange to trade ETH for tokens. It will dynamically calculate token prices based on what is left in the contract. The contract owner will get some fees back.
Owner gets a passive fee income. But they have their capital locked up.
Token buyers are happy because they get small transaction fees, it is a trustless exchange.
Can come up with ideas, just deploy it out into production and see how it goes. Make sure you verify your source on Etherscan.
Allows anyone to just come up with ideas and get it out there.
Make sure you share your findings, so the ecosystem learns.

Casper the Friendly GHOST: A correct-by-construction blockchain – Vlad Zamfir

All the Ethereum proof of stake research projects are with the goal around finality safety.
Traditional consensus protocols decide on one block of transactions at a time.
Point of PoS is to incentive nodes to do the right thing. Need to prove that it is fault tolerant, and when there are faults, that it can recover (and penalise the bad actors).
Vlad just talks too fast and clicks back and forth through slides too fast to keep track of notes sorry.


Introducing the TrueBit Virtual Machine – Jason Teutsch

Is now deployed to testnet
Smart contracts can only handle limited computation execution time.
Truebit is a scaling solution for computation. Do the heavy work off chain. Uses interactive verification for large transactions. Help to bypass the gas limit.
Is an ethereum smart contract + a new off chain architecture.
Solver proposes the solution, submits it. Anyone can challenge it and put up a deposit. They play the verification game to see who was correct, loser loses deposit.
Computation runs in a TrueBit Virtual machine. Tasks must compile and run across all machines. The TVM breaks it down so that the smallest piece of execution can run on chain. For when there is a disagreement, the one step where people got a different result can be run on chain to determine the correct result.


Scaling Ethereum Smart Contracts – Joseph Poon

Many blockchains on a blockchain. Can bond your private chain to the public network.
Deploy a plasma smart contract to the main blockchain. Can now run your own child plasma chain. Periodically commit block hashes to the main chain contract.
Big changes can happen on the plasma chain, but just a tiny block hash is submitted onto main chain.
People can submit a merkalised proof if someone tries to commit an incorrect hash to the main chain.
If someone is withholding block data and isn’t letting it continue, then you can exit the child chain, have eth roll back up to the main chain, and then create a new child plasma chain
Could credibly securely spin out these plasma chains to scale computation for specific use cases. Like a Reddit comment chain, ebay chain.
The point is to encompass all worldside computation. Computation can be done on child chains, with final state committed to the main root chain.

ZoKrates: A Toolbox for zkSNARKs on Ethereum – Jacob Eberhardt
On chain processing is submitted as a transaction. Is executed + validated on chain.
Off chain processing, the transaction is executed off chain. Just the validation happens on chain.
Means that private information can be used without revealing it.
Truebit is one way of doing this. Another is using zkSNARKS
zkSNARKS, verification cost is independent of computational complexity. Short & non-interactive proofs.
Define computation as mathematical circuits. But is very complex to create these yourself.
I like thinking of this as: Hashes lets you verify large pieces of data as a small hash value. zkSNARKS allows you to represent a large complex execution as a tiny proof.

ZoKrates wants to provide tooling to make it easy to support zkSNARKS from end to end. And to integrate easily into Ethereum. It has a DSL to specify your computation, has a compiler into provable constraint systems, support for the phases (setup, witness, etc), and a contract to verify the computation on chain.
On chain verification currently costs about 1.6m gas.


Designing Maximally Verifying Light Clients and Sharding- Vitalik Buterin


Watch this session.

Subtitled as “a modest proposal for Ethereum 2.0 over the next 4 years”
Ethereum works. Many applications. High adoption >460k tx/day. Which is about 7tx/sec
Ethereum nodes worldwide. US has 30%, Canada 5%, Australia 2.8%
The Byzantium fork added in privacy preserving features, that will enable zkSNARKS, ring signatures.
Scalability is still a current challenge. Right now every node runs every transaction. And transactions are not parallelisable.
Sharding is a way to split up the blockchain state. Only allow async calls between shards. Each node only processes transactions for a shard, so a small portion of all network transactions.
Governance & protocol evolution has been a challenge. Hard forks making deep changes are hard. Long time to code, test, and a high risk of consensus bugs.
But we want to make some big changes to enable Ethereum 2.0 (EVM upgrades, more precompiles, etc.). How do we handle the trade off.

1 blockchain 2 systems:


Have a Validator Manager Contract. Runs a PoS system. Would keep track of validators, to join and leave as a validator. Each validator can gets assigned to shards randomly, can make blocks. Block making protected by rewards and slashing.
Connecting the shards go through the contract via messages.
Gives a way to experiment with this as a contract, with less risk on the main chain, and doesn’t require a hard fork.
Can evolve shards quickly, will letting main chain be more conservative.

Sharding roadmap


Having shards will allow experimentation with backwards incompatible upgrades:
EVM upgrades like EVM1.5 & ewasm.
Stateless clients

For stateless clients, consensus nodes would not need to hold state, only state root.
Would only need to submit merkle branches to submit state changes.
Means you don’t need to store and read state from disk any more. Makes it easy to shuffle validators around as they don’t need to sync down entire state, just accept merkle branches for changes.