SECRET COMMUNICATION AND AUTHENTICATION SCHEME BASED ON PUBLIC KEY CRYPTOSYSTEM USING N-ADIC EXPANSION

摘要

A secret communication and authentication scheme based on a public key cryptosystem in which a decryption speed is improved while maintaining a security level. In the RSA type secret communication, a plaintext is expressed in a form of a k-digit n-adic number and a ciphertext is obtained by applying a calculation using the first public key n and the second public key e to the n-adic number and transmitted. Then, from the received ciphertext, a lowest digit of the n-adic number is decrypted by using the first public key n and the second secret key d, upper digits of the n-adic number are sequentially decrypted by using a decrypted value of the lowest digit of the n-adic number at the receiver side, and the plaintext is recovered by using decrypted values of respective digits of the n-adic number. The Rabin type secret communication can also be realized by the similar scheme. Moreover, the same principle of the n-adic pubic key cryptosystem can also be used in realizing the RSA type or the Rabin type Authentication.