Encryption method, program for encryption, memory medium for storing the program, and encryption apparatus, as well as decryption method and decryption apparatus

摘要

The present invention relates to a cryptosystem. A keystream table ÄKsÜ is a virtual data space. Every data of 1 byte in a secondary ciphertext E2 provides a vector directional component IR. The data Ks (IR) in the keystream table ÄKsÜ designated by the directional component IR of the vector is recognized as the quantitative component of the vector. By handling a secondary ciphertext E2 of 1 byte as the address in the keystream table ÄKsÜ, the secondary ciphertext E2 can be recognized as the directional component of the vector. A logical operation for the data Ks (IR) is performed, and the internal vector data V is sequentially replaced every 1 byte. An exclusive OR operation is performed between the internal vector data V and the primary ciphertext E1 for generating a secondary ciphertext E2.