Patent ID: 6341273
Filing Date: 2002-01-22
Classification: G06Q,G07F

Abstract:
A method of operating a digital payment transaction system comprising:a) at a first party, generating a secret number; b) storing at the first party the secret number; c) generating at the first party a first hash chain of values which are derived from the secret number by successive operations of a hash function; d) communicating to a second party a digitally encoded value from the chain of hash values subsequent to the first value; e) generating at the second party a second hash chain of values which are derived from the value communicated by the first party in step (d); f) communicating digitally encoded values from said second hash chain to a third party in payment; and g) subsequently communicating to the second party from the first party a monetary value represented by a value in said hash chain which precedes the value originally communicated in step (d).