Identity protocol v1

From Bitcoin Wiki
Revision as of 04:25, 28 June 2013 by Jgarzik (talk | contribs) (Creating root record: simplify (h/t petertodd))
Jump to: navigation, search

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 ( = "John Smith").

Creating sacrifice transactions

Similar to Announce/Commit Sacrifices

  1. TM = current block height
  2. create transaction T2.
    1. must include OP_RETURN <digest of master pubkey> output
    2. nlocktime = TM + 144 blocks
    3. no more than 1000 bytes in size
  3. create transaction T1
    1. must include >= 0.01 BTC fee
    2. must include OP_RETURN txid(T2) output
    3. no more than 1000 bytes in size
  4. broadcast T1, T2 until confirmed

Creating root record

Craft a bytestream that represents the root SIN record.

  1. MPK = master public key
  2. B1 = block w/ T1, B2 = block w/ T2
  3. Verify B2 height >= 144 blocks of B1 height. Fail and waste sacrifice if not.
  4. MD = ripemd160(MPK)
  5. Prefix = 0x18, SIN_Version = 0x01
  6. SIN = base58_encode_check( Prefix + SIN_Version + MD )
  7. PPK = Preferred Public Key, new public key for root of trust
  8. Build root record,
    1. SIN
    2. MPK

Thus a minimal root record is

  • SIN
  • 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.