基于字的流密码的分布式解密

该文分析了Magnus berg提出的简单加法流密码的分布式解密方案，指出了其最主要的缺点是：加解密要在不同的有限域内进行、加解密运算所依赖的域的阶必须为素数而且要满足一定的关系。提出了基于字的流密码的分布式解密方案。新提出的方案有两个主要优点：一是将加解密统一在同一个有限域内进行，且域的阶不再要求是素数；二是在安全性和效率两方面比原有方案均有了明显的提高。在应用方面，新方案可应用于诸如数据库信息的保护，Ad-hoc网中分布式密钥管理，等等。

Distributed Decryption of Word-Oriented Stream Ciphers

The distributed decryption scheme for simple addition stream ciphers proposed by Magnus Öberg is analyzed. Its main disadvantages, i.e. the operations of encryption and decryption are implemented in different finite fields, and the orders of the two fields must be primes satisfying a certain relation, are pointed out. A new distributed decryption scheme for word-oriented stream ciphers is presented. Compared with Magnus Öberg’s scheme, the proposed scheme has two main advantages. Firstly, in the new scheme, the encryption and decryption operations are implemented in the same finite field, and the size of the field is not required to be a prime. Secondly, the security and efficiency of the new scheme are greatly improved. For applications, the new scheme can be applied in the protection of data confidentiality in a database, distributed key management in Ad-hoc networks, etc.