Patent ID: 9240884
Filing Date: 2016-01-19
CPC Classification: H04L

Claim Text:
1. A computer implemented method of generating a private key and a corresponding public key of a correspondent in a communication system, the correspondent having a cryptographic unit, the method comprising: said cryptographic unit generating a digital signature; said cryptographic unit obtaining message data; said cryptographic unit generating a self-signed signature message by combining said message data and said digital signature; and said cryptographic unit computing said private key using said self-signed signature message and computing said corresponding public key using said private key such that said corresponding public key is verifiable using said digital signature and said self-signed signature message; wherein the digital signature includes an integer, and said generating said self-signed signature message by combining said message data and said digital signature includes concatenating said message data and said digital signature into said self-signed signature message; and wherein said computing said private key and said corresponding public key includes: said cryptographic unit computing a message digest from an integer hash value of said self-signed signature message, said cryptographic unit computing said private key from said digital signature and said message digest, said cryptographic unit computing said corresponding public key from said private key, and said cryptographic unit sending said corresponding public key to a certification authority with information to allow said certification authority to confirm an identity of said correspondent, and issue a certificate once said identity has been confirmed, and said certificate authority is a second computer system which is separate from a first computer system with the cryptographic unit of the correspondent.