We will create a simple datastore solution using IPFS and Ethereum. IPFS provides a convenient interface for distributed data storage, with a hash-based content address for reference to our file. This address will be stored in our smart contract on a private Ethereum blockchain. To retrieve the latest data, we will fetch the address from our blockchain and query IPFS for the associated file.

This repository has the following dependencies:

• IPFS - the Interplanetary File System
• Geth - the Go implementation of Ethereum

Mac: For Mac users, install Homebrew and update:

brew update
brew upgrade

Then run:

brew tap ethereum/ethereum
brew install ethereum

Windows: For Windows users, download the latest stable release, extract it, download the zip file, extract geth.exe from zip, open a command terminal and type:

chdir <path to extracted binary>
open geth.exe

Linux: For Ubuntu users, run:

sudo apt-get install software-properties-common
sudo add-apt-repository -y ppa:ethereum/ethereum
sudo apt-get update
sudo apt-get install ethereum

Mac/Linux: For Mac and Linux users, download the prebuilt package, then untar and move the binary to your executables $PATH as follows:

tar xvfz go-ipfs.tar.gz
mv go-ipfs/ipfs /usr/local/bin/ipfs

Windows: For Windows users, download the prebuilt package, then unzip and move ipfs.exe to your %PATH%.

To test that your IPFS installation worked, in your terminal (Mac/Linux) or command prompt (Windows) window, run:

ipfs help

The help menu describing IPFS actions will be printed out.

We will start by setting up a private Ethereum blockchain on your local machine.

Create a new directory for your private blockchain. In your terminal (Mac/Linux) or command prompt (Windows) window, navigate to the directory and create a new account:

geth --datadir="./" account new

Enter a password when prompted for your local Ethereum account. Geth will create a keystore directory and store the account file in the keystore.

Setting up a private blockchain requires defining a genesis block, which sets the initial parameters and token distribution.

In the directory containing your account, copy/paste/save the following JSON into a file called genesisblock.json:

{
    "config": {
        "chainID"       : 10,
        "homesteadBlock": 0,
        "eip155Block":    0,
        "eip158Block":    0
    },
    "nonce": "0x01",
    "difficulty": "0x20000",
    "mixhash": "0x00000000000000000000000000000000000000647572616c65787365646c6578",
    "coinbase": "0x0000000000000000000000000000000000000000",
    "timestamp": "0x00",
    "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
    "extraData": "0x00",
    "gasLimit": "0x2FEFD8",
    "alloc": {
    }
}

This will be block 0 of your private blockchain. If you ever wish to have others join this network, they will need this genesis block as well.

We will now instantiate the blockchain network and load the geth console:

geth --datadir="./" init genesisblock.json
geth --datadir="./" --networkid 23422  --rpc --rpccorsdomain="*" --rpcport="8545" --minerthreads="1" --mine --nodiscover --maxpeers=0 --unlock 0 console

The --datadir flag tells geth the path for storing blockchain data. The --networkid flag gives your private blockchain a unique reference ID. The --rpc and related flags enable remote procedure call (RPC) functionality for web3. The --minerthreads flag enables the specified number of CPU threads for mining. The --mine flag indicates the mine function for processing transactions and propagating smart contracts through the network. The --nodiscover and --maxpeers flag disables peer discovery mechanisms. The --unlock 0 flag unlocks the first account in the system. The --console flag enables the REPL terminal.

As this is our first time running the --mine flag, wait for the DAG file to be generated. You will see Generating DAG: xx% for a couple minutes. This is a one-time operation.

While we wait for the DAG to be generated, let's setup IPFS. Start by initializing IPFS and modifying CORS restrictions:

ipfs init
ipfs config --json API.HTTPHeaders.Access-Control-Allow-Origin '["*"]'
ipfs config --json Gateway.HTTPHeaders.Access-Control-Allow-Origin '["*"]'

Now start the daemon:

ipfs daemon

Open storage.html and follow the instructions on the front page.

Below are references, projects, and developing work related to IPFS and Ethereum.

• IPFS - A peer-to-peer hypermedia protocol to make the web faster, safer, and more open.
• astralboot - Low level boot server that deploys directly out of IPFS (TFTP, PXE Boot).
• ipget - wget for IPFS: retrieve files over IPFS and save them locally.
• container-demos - Demos on how to boot docker images and VMs from IPFS.
• ipfs-npm - npm on IPFS.
• luckychain - Intel SGX and IPFS-based blockchain implementing Proof of Luck.

• Ethereum - Ethereum is a decentralized platform that runs smart contracts: applications that run exactly as programmed without any possibility of downtime, censorship, fraud or third party interference.
• web3.js - the Ethereum compatible JavaScript API which implements the Generic JSON RPC spec.
• Ethereum Javascript API (web3) - Web3 JavaScript Ðapp API.

• akasha - A Next-Generation Social Media Network, powered by Ethereum and embedded into IPFS.
• digix - An asset-tokenization platform built on Ethereum and IPFS.
• embark - A framework that allows you to easily develop and deploy Decentralized Applications (DApps).
• eris - An application platform for building, testing, maintaining, and operating applications built to run on an ecosystem level.
• uport - A mobile, self-sovereign identity and key management system, built on the Ethereum blockchain.
• js-deflate - Gzipping of data to make it fit in URLs

The Ethereum Foundation and Ledger Labs have provided the original Ethereum contract resources.