一种新的公钥密码体制和签名方案

文章提出一种新的安全性基于离散对数难题的公钥密码体制，以及安全性基于大整数分解难题的签名方案．与RSA体制和ELGAMAL体制相比，该密码体制能抵抗通过将一个密文表示成其他已知明文的密文的幂乘来求得该密文所对应的明文的攻击，该签名方案能抵抗通过已知的消息-签名对相除得到某些消息的签名的攻击，同时该密码体制和签名方案不需要使用随机数生成器生成加密参数，也不需要避免该参数的重复使用．在对该密码体制和签名方案进行分析后，得出该密码体制和签名方案是安全的．

A Novel Public Key Cryptosystem and Signature Scheme

A novel cryptosystem and signature scheme are proposed, in which the security of this cryptosystem depending on the difficulty of computing discrete logarithm, and the security of this signature scheme depending on the difficulty of factoring large integers. Compared with RSA and ELGAMAL, this cryptosystem can resist the attack that the plaintext can be easily calculated if its cipher can be represented by exponent product of other ciphers whose plaintexts are known; this signature scheme can resist the attack that the signature of message can be easily forged if this message can be represented by quotient of two other messages whose signatures are known, at the same time in this cryptosystem and signature scheme the random number generator isn＇t used and the encrpytion parameter can be reused. After analysed and evaluated, this cryptosystem and signature scheme are secure.