Ethereum Name Service

Nick Johnson <nick@ethereum.org>

Why do we need another name service?

What makes a good name service?

Separation of concerns
Distributed authority & implementation
Forward-compatibility
Efficient on-chain resolution

Components of ENS

ENS Registry

Namehash

nick.wallet.eth.

Namehash

nick.wallet.eth.

Namehash

SHA3(eth)SHA3(wallet)SHA3(nick)

Namehash

SHA3(eth)SHA3(wallet)SHA3(nick) 0x4f5b81270x46a31f1f0x5d5727cb

Namehash

SHA3(eth)SHA3(wallet)SHA3(nick) SHA3(0, 0x4f5b8127)0x46a31f1f0x5d5727cb

Namehash

SHA3(eth)SHA3(wallet)SHA3(nick) SHA3(0, 0x4f5b8127)SHA3( , 0x46a31f1f)0x5d5727cb 0x93cdeb70

Namehash

SHA3(eth)SHA3(wallet)SHA3(nick) SHA3(0, 0x4f5b8127)SHA3(0x93cdeb70 , 0x46a31f1f)SHA3( , 0x5d5727cb) 0x4bcc8335

Namehash

SHA3(eth)SHA3(wallet)SHA3(nick) SHA3(0, 0x4f5b8127)SHA3(0x93cdeb70 , 0x46a31f1f)SHA3(0x4bcc8335 , 0x5d5727cb) 0xefcbf86e

Resolvers

contract SimpleResolver is owned {
    mapping(bytes32=>address) addresses;

    function has(bytes32 node, bytes32 kind)
            constant returns(bool)
    {
        return kind == "addr" && addresses[node] != 0; 
    }

    function addr(bytes32 node) constant returns(address)
    {
        if(addresses[node] == 0)
            throw;
        return addresses[node];
    }

    function setAddr(bytes32 node, address addr) owner_only
    {
        addresses[node] = addr;
    }

    function()
    {
        throw;
    }
}

Registrars

contract FIFSRegistrar {
    ENS ens;
    bytes32 rootNode

    function FIFSRegistrar(ENS _ens, bytes32 _rootNode) {
        ens = _ens;
        rootNode = _rootNode;
    }

    function register(bytes32 label, address newOwner) {
        address owner = ens.owner(sha3(rootNode, label));
        if(owner != 0 && owner != msg.sender)
            throw;

        ens.setSubnodeOwner(rootNode, label, newOwner);
    }
}

Auction-based registration

Only names under .eth are available
Names are auctioned off using a blind second-price auction
Names shorter than 7 characters are prohibited
Winning bidders' deposits are held in contract accounts
Users can recover deposit by abandoning name
...or, transfer name and deposit to the permanent registrar

An interim solution

Questions and comments?

nick@ethereum.org

https://gitter.im/ethereum/go-ethereum/name-registry

https://github.com/ethereum/EIPs/issues/137