Patent ID: 7600121

Claim:
A computer-implemented method of electronically transmitting an e-mail message from a first user having a first terminal to a second user having a second terminal, comprising the steps of: a) electronically transmitting an e-mail message in an encrypted form together with a dynamic serial number corresponding to said message by a first terminal to a second terminal, said encrypted message being encrypted prior to transmission by means of a key generated by a first key generator using a seed; b) providing to and storing said seed in said second terminal; c) receiving said message with the dynamic serial number at said second terminal and using said dynamic serial number to identify said key used to encrypt said message and a sequential order of said message; d) synchronising a counting value in each terminal; e) using said dynamic serial number, said seed and said counting value by said second terminal to independently generate said key used to encrypt said message; f) decrypting said encrypted message at said second terminal using said independently generated key; g) based on said seed, generating a list of entrusted terminals; and h) accepting e-mail messages only from registries in said list.