Identity protocol v1

Design goals

Decentralized identity.

• Has some creation cost
• Sacrifice may be digitally proven, bootstrapping root of trust from blockchain data
• Start as anonymous; opt out of anonymity by attaching identifying key-value pairs (real.name = "John Smith").

Creating sacrifice transactions

Similar to Announce/Commit Sacrifices. The author's feedback on this protocol was very helpful.

1. MPK = master public key
2. TM = current block height
3. create transaction T2.
   1. must include OP_RETURN ripemd160(MPK) output
   2. nlocktime = TM + 144 blocks
   3. no more than 1000 bytes in size
   4. must include >= 0.001 BTC fee
4. create transaction T1
   1. must include OP_RETURN serialized(T2) output
5. broadcast T1, T2 until confirmed

Creating a SIN

A SIN is the unique record identifier by which this identity will be known.

1. Prefix = 0x18
2. SIN_Version = 0x01
3. MD = ripemd160(MPK)
4. SIN = base58_encode_check( Prefix + SIN_Version + MD )

Validating the root identity information

1. B1 = block w/ T1, B2 = block w/ T2
2. Verify B2 height - 144 >= B1 height. Fail and waste sacrifice if not.
3. Verify mined T2 == announced T2

Thus a minimal root record is MPK and is provably

• linked to the sacrifices
• MPK starts a new chain of digital signature trust, for further record updates

After that, additional key-value pairs may be associated with the root record via updates verified by PPK, stored in an alt-blockchain or DHT somewhere. That is outside the scope of this minimal document.