Patent ID: 7110539

Claim:
A method of encrypting data suitable for sending to a decrypting party, said method including the steps of: (a) dividing said data into data segments; (b) accepting at least a cryptographic key k shared with the decrypting party; (c) generating the ith segment key s i for each corresponding ith data segment (i=1, 2 . . . ,) to be encrypted, the ith segment key s i being generable using a sequence generating function with said cryptographic key k and some accessory data strings as inputs; (d) encrypting the ith data segment using a ciphering function with s i as the encryption key to form the ith ciphertext segment; and (e) outputting the ith ciphertext segment, and at least a part of said accessory data strings for sending data to the decrypting party, and if more data segments are to be encrypted, repeating steps (c), (d) and (e).