Smart contract interaction out of the coldest of storage (Devcon5)
Devcon 5 · 22 Nov 2019 · 5:17
This Devcon5 talk covers smart contract interaction from cold storage, the question of how to safely sign and submit a transaction when the private key involved is deliberately kept offline and disconnected from the internet. It covers the practical workflow tradeoffs between that level of key security and ease of everyday use.
Speakers
Topics
From Devcon 5, hosted by Ethereum Foundation.
Transcript
[Applause] hello my name is max clavicle I am an engineer with coinbase custody I am extremely excited to be here today in as you can see my talk is titled smart contract interaction out of the coal business direction so at point-based custody we provide friction as a teacher we introduced barriers that make it extremely difficult for attackers to steal our customers funds we take our private keys char them up into many many pieces it's sort of them completely off flush we
only use any given address once to sign transactions and then we roll over the customers funds to a new address and we also have a very talented ops team who personally verify each transaction so these features differentiate ourselves from our competitors they are the reason why more people choose us to hold their crypto than any other custodian on the planet and so we support many currencies but as the most successful smart contract platform etherium provides unique challenges to how our system works so you know our top-of-the-line security comes out of the box you know you're either safe but
we don't be struggle to do some of the things that make a theorem the most exciting platform so as far as interacting with contracts that require high transaction girl but like governance or any meeting or you name it you know since it takes a non-trivial amount of time for us to reconstruct the keys you know we start to do that you know and for interacting with smart contracts like in traversing the way that require funds to stay put we simply can't support that out of the box since we roll over our funds to a new address Kotaku sign but I point base custody you take a cue from my manga hero yabai city here and we surpass events right here right now
so how do we do that I will introduce to you the proxy smart contract better that we use so using this pattern we can continue to provide world-class security while also giving our users originalist user experience so how does it work let's say we want to let our customers projects participate in major governments what a coincidence so whenever we approached a new integration we start by writing a customized proxy contract that fits around the external contract length of life so as you can see there aren't really a lot of bells and whistles you know we just create a thin aside over
the external contract and we call the external contract methods using the proxy contract that's the identity and so when we're on board a new customer to one of these integrations we start by pairing them with a hot address with a tiny bit of ether in it just to make contract call us opinions we then use that address to deploy a contract on behalf of the customer and we designate a new cold storage address the return address that the funds will ultimately arrive and so once the contract is deployed we move the customers whole balance of either either or tokens to the contract depending on what it's
trying to and once the funds are in the contract the fund can really begin we can use the hot address to make as many quick and risk for any contract falls to the external contract possible using the proxy as the bridge since the proxy has the customers full balance they don't find the influence on any of these networks in nature so if you're voting for maker governance voting environment if you're signaling for edge for signaling you're signaling authority it's there there is still able to wield the full EFT of their principle and when customers are done interacting with the process contracts we call that
previously Toronto visa will send the funds back to safety with old storage so with this cop witness pattern were able to smash our limits we're able to continue to provide world-class security while also giving our users a frictionless customer experience while interacting with extra context our enemy hero y'all may see the euro is brown so that's my talk thanks bro this name my name is nest [Applause]