Proof of Existence Demo
Coding Challenge - Due Date, Thursday October 26 2017 - Smart contract + AI
This weeks challenge is to create an app that uses both Ethereum Smart Contracts an a machine learning model together. Possible ideas are this repository. You can re-implement that if you'd like. Doing something as simple as sending model training timestamps to a blockchain also work. Have fun and good luck!
Overview
This is the code for this video on Youtube by Siraj Raval on how smart contracts work. This is the code for a proof of existence smart contract, a digital notary without needing to hire a lawyer. More detailed instructions can be found here.
Usage
# Run the testrpc ethereum blockchain
$ npm install -g ethereumjs-testrpc
$ testrpc
# First, let's install truffle
$ npm install -g truffle
# let's setup our project
$ mkdir solidity-experiments
$ cd solidity-experiments/
$ truffle init
# truffle compile
$ truffle migrate
$ truffle create contract ProofOfExistence
Interacting with the contract via the truffle console looks like this
$ truffle console
// get the deployed version of our contract
truffle(default)> var poe = ProofOfExistence1.at(ProofOfExistence1.address)
// and print its address
truffle(default)> poe.address
0x3d3bce79cccc331e9e095e8985def13651a86004
// let's register our first "document"
truffle(default)> poe.notarize('An amazing idea')
{ tx: '0x18ac...cb1a',
receipt:
{ transactionHash: '0x18ac...cb1a',
...
},
logs: [] }
// let's now get the proof for that document
truffle(default)> poe.proofFor('An amazing idea')
0xa3287ff8d1abde95498962c4e1dd2f50a9f75bd8810bd591a64a387b93580ee7
// To check if the contract's state was correctly changed:
truffle(default)> poe.proof()
0xa3287ff8d1abde95498962c4e1dd2f50a9f75bd8810bd591a64a387b93580ee7
// The hash matches the one we previously calculated
Credits
The credits for this code go to maraoz. I've merely created a wrapper to get people started.