NTRU公钥密码体制的等价密钥

Equivalent Keys in NTRU Public Key Cryptosystem

NTRU公钥密码体制存在多个私钥对应同一个公钥的问题。首先分析了NTRU成功解密的条件,提出NTRU等价密钥的概念。然后给出了NTRU截尾多项式环上多项式可逆的充分必要条件和NTRU|.|∞半范数的相关性质,提出4种等价密钥的构造方法。最后分析了NTRU等价密钥对NTRU安全性的影响。分析表明,NTRU参数选择不当会导致一些特殊形式的等价密钥存在,严重威胁安全性。

NTRU public Key cryptosystem has the problem that multiple private keys correspond to a common pubic key. Firstly the condition of decryption was discussed, and the conception of equivalent keys in NTRU was proposed. Secondly the invertibility of polynomials in truncated polynomial ring and the ｜. ｜∞ semi-norm were discussed, and four schemes to construct equivalent keys were presented. Finally the security effect of equivalent keys was analyzed, which indicates that if NTRU parameters are not chosen properly, some special equivalent keys will pose a serious security threat to NTRU.