高效的适应性选择密文安全公钥加密算法

The Efficient CCA Secure Public-Key Encryption Scheme

安全高效的公钥加密算法是信息系统安全的重要保障技术,文中利用陷门承诺函数的思想实现对密文完整性的保护,由此在标准模型下给出一个可证明适应性选择密文攻击安全的公钥加密算法.新算法与著名的CS98公钥加密算法相比公钥参数数量减少20%,私钥参数减少80%;与BMW05公钥加密算法比较,公、私钥参数数量大为减少且安全规约效率显著提高.新算法支持公开的密文完整性验证,具有精简的公、私钥参数数量,其安全性被证明高效地归约为GHDH数学难题假设.

The security and efficient public key encryption algorithm is an important technology guarantee for security of information systems.This paper uses an idea of trapdoor commitment function to protect ciphertext integrity,thus presents a provable public-key encryption（PKE） scheme in the standard model,which is secure against adaptive chosen ciphertext attacks（CCA）.The new encryption scheme is very efficient： Compared to the previously most famous scheme by Cramer and Shoup（CS98） it has 20% shorter public keys and 80% shorter secret keys;compared to the scheme by BMW05 it has shorter public/secret keys and has tighter and simpler security reduction.The new encryption scheme supports public ciphertext integrity verification,has short public/secret keys,and its security proved reduces to the Gap Hashed Diffie-Hellman（GHDH） assumption tightly.