ID Backup



This is a proposal for a method that would allow generation of bitcoin addresses tied to one’s identity, and not to stored data. This would in theory allow someone to send funds to himself in a way that ensures it will be possible to use those funds at any time in the future.

This should be used by people willing to “save” funds without having to rely on any third party service, and should be implemented in the bitcoin client, and not on a remote site.


The idea is to generate the ECDSA private key not from a random source, but from a SHA256/SHA512 hash of the previous informations, cut to the appropriate format.


Each string data is prefixed of 2 bytes (little endian) containing their length, and must be represented as UTF-8

  • Last Name
  • First Names
  • Birth name (if not different, skip)
  • Birth date in string format (YYYY-MM-DD)
  • Birth country (country code, 2 letters)
  • Birth city
  • Blood type (one of: A, B, AB, O)
  • Passphrase (up to the user)
  • 8 bytes integer “serial” (little endian), used to generate different keys for a single individual

It is possible to generate multiple addresses for a single individual by incrementing “serial”. The software should initially increment “serial” until at least 100 concurrent addresses which have never been broadcasted on the blockchain are found.


This is yet just a proposal, analysis is welcome


See Also on BitcoinWiki