| 摘要 |
PROBLEM TO BE SOLVED: To provide an encryption system and a decryption system performing high speed processing safely. SOLUTION: A function selection means, for each block unit of a document from a document storage means, selects a function sequentially by pseudo-random numbers. A function execution means, using a block of the pseudo-random number sequence as a parameter in the selected function, converts the document to encrypt it. In the decryption system, an inverse function selection means, for each block unit of the encrypted document from the encrypted document storage means, selects an inverse function by pseudo-random numbers. An inverse function execution means, using a block of the pseudo-random number sequence as a parameter in the selected inverse function, converts the encrypted document to decrypt it. Since the respective functions are basic high-speed functions, the combined overall conversion is also carried out at high speed. Since both of the combination of the functions and the number of iteration can be changed, specification reinforcement in the future is facilitated. The execution order of the functions cannot be known, and consequently high safety is ensured. COPYRIGHT: (C)2011,JPO&INPIT |
