CRYPTOGRAPHIC METHOD AND DEVICES FOR FACILITATING CALCULATIONS DURING TRANSACTIONS

摘要

The invention concerns a cryptographic method for use in a transaction for which a first entity (A) generates by means of a private RSA key (d), a proof verifiable by a second entity (B) by means of a public RSA key associated with said private key. The public key comprises a first exponent (e) and a module (n). In said method, the first entity (A) generates a first element of proof (x) whereof one calculation can be obtained independently of the transaction and a second element of proof (y) related to the first element of proof (x) and which depends on a common number (c) shared by the first and the second entities specifically for the transaction. The second entity (B) verifies that the first element of proof (x) is related by a relationship to a first modulo power of the module (n), of a generic number (g).