| 摘要 |
<p>PURPOSE: To provide a ciphering device and a cipher system particularly excellent in the deciphering speed as compared with RSA ciphers in use. CONSTITUTION: This device is provided with a key generation means 14 which generates primes p and q and at the time of computation with dp and dq satisfying dp =(1/e)mod(p-1), dq =(1/e)mod(q-1), where an integer e is mutually prime with the least common multiple of the product n=pq, (p-1) and (q-1), sets the product n and an integer e to be public keys and sets the primes p, q and dp , dq to be secret keys. In addition the device is provided with a ciphering calculation means which makes an integer pair of inputted plain texts correspond to a point on a cubic curve, determines a point obtained by e-folding the point by the use of the public keys by arithmetic on the cubic curve, and outputs arithmetic results as a cipher text, and a deciphering arithmetic means which subjects the integer pair of the inputted cipher text to homomorphic transformation, then raises the result to the dp -th power under a divisor p and dq -th power under a divisor q, and synthesizes them by the use of the Chinese remainder theorem to output a plain text.</p> |
