NAYUTA：一种基于分组密码的加密算法

NAYUTA: An Encryption Algorithm Based on Block Ciphers

摘要: 分组密码作为对称密码的一个重要分支，在保护信息安全方面具有重要作用；当今主流的分组密码算法有DES、AES、SMS4等加密算法。该算法作为基于分组密码设计的加密算法，选取分组密码的K空间中的密钥元素作为置换依据对密文进行置换，并在置换完毕后将密钥插入密文中，通过函数将密文中的所有块和密钥进行处理并发送。相较于其他的加密算法，NAYUTA主要面向即时通讯，利用密文–密文验证的双因子验证模式和密文–密文验证的双因子混合模式，增加了统计学分析攻击的难度，同时也保证了密文信息的可信性和完整性。对于双因子验证模式的处理函数而言，该模式是一种基于时间的对称加密方式，使得加密近似于理想OTP (One-Time Password)的加密方式。NAYUTA目前已将在软件层面和硬件层面均有实现。

Abstract: As an important branch of symmetric ciphers, block ciphers play an important role in protecting information security; today’s mainstream block cipher algorithms include DES, AES, SMS4 and other encryption algorithms. As an encryption algorithm designed based on block cipher, the algorithm selects the key element in the K space of the block cipher as the replacement basis to replace the ciphertext, and inserts the key into the ciphertext after the replacement is completed, and processes and sends all blocks and keys in the ciphertext through the function. Compared with other encryption algorithms, NAYUTA is mainly oriented to instant messaging, and uses the two-factor authentication mode of ciphertext-ciphertext verification and the two-factor hybrid mode of ci-phertext-ciphertext verification, which increases the difficulty of statistical analysis of attacks and ensures the credibility and integrity of ciphertext information. For the processing functions of the two-factor authentication mode, this mode is a symmetric time-based encryption method, which makes the encryption similar to the ideal OTP (One-Time Password) encryption method. NAYUTA will now be implemented at both the software and hardware levels.