关键词: 公钥密码, 比特安全, NTRU, 可展性, 预言机

Abstract:

Based on the malleability, the bit security for NTRU is proved in a simplified decision model. In the model, the oracle can obtain the goal plain text through a sequence of queries if the oracle can output the parity of summation of coefficients in the goal plain text. Compared to the work of Mats, the model is simple and consistent with the decryption process of NTRU. Finally, the relationship between bit security and indistinguishability of encryption scheme is analyzed and the result shows that the formal definition of strong security is of great practicability.

Key words: public key cryptography, bit security, NTRU, malleability, oracle