PSEUDO RANDOM NUMBER SEQUENCE GENERATING DEVICE, ENCRYPTION AND DECRYPTION DEVICE, PSEUDO RANDOM NUMBER SEQUENCE GENERATING METHOD, ENCRYPTION AND DECRYPTION METHOD, PSEUDO RANDOM NUMBER SEQUENCE GENERATING PROGRAM, AND ENCRYPTION AND DECRYPTION PROGRAM

摘要

PROBLEM TO BE SOLVED: To enable generation of a pseudo random number sequence, encryption and decryption by using mapping conversion such as two-dimensional cat map which has been conventionally said to be unsuitable for pseudo random number sequence generation, encryption, or decryption.

SOLUTION: An n-dimensional vector sequence S(1), S(2), ..., S(K)of a w-bit integer received by a seed reception section 10 is provided to an initialization section 11 to obtain an n-dimensional vector sequence X(1), X(2), ..., X(K)of a w-bit integer. After mapping conversion using a conversion matrix determined from the n-dimensional vector sequence X(1), X(2), ..., X(K)is applied by the converting section 12, a rotation operation of the prescribed number of rotation bits is performed to a part or the whole of it by a rotation section 13. The result is updated by an updating section 14, and mapping conversion and rotation operation are repeated prescribed times by the conversion section 12 and the rotation section 13 respectively. Thus, a multi-dimensional pseudo random number sequence having high randomness is generated.

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