Abstract:  Users have to manage and remember more and more accounts and passwords with the application of all kinds of information systems. Designing a novel, simple, convenient, secure and adaptive encryption policy is becoming urgent requirement, using which the users can realize their own encryption algorithm. This paper proposes a novel strength adaptive encryption policy and a relevant algorithm framework. The encryption algorithm includes three sub-modules, e.g. Hash mapping, blank filling and character encryption. The Hash mapping is used to make password book, and is responsible of placing clear-text or obtaining cipher-text from the buffer according to the password book. Blank filling is used to fill some random characters in the buffer to enhance the security. Character encryption is used to encrypt the character by certain encryption algorithm that the users choose themselves. Through the encryption policy, all users can have their own and specific encryption algorithm according to the practical need. Both the theory analysis and experiments prove that the encryption algorithm is flexible, convenient and secure enough. The theory analysis also proves that it is impossible to crack the password using enumeration method if there is no the correct secret key.

Key words: encryption strength adaptive, text encryption, Hash mapping

摘要： 各类信息服务系统在生活中各领域的广泛应用导致用户需要管理和记忆越来越多的账号和密码，设计一种让用户能够根据实际需求自定制的、加密强度可调节的账户和密码管理方法成为急需解决的问题。提出了一种加密强度可定制与调节的加密策略，并设计、实现了一个加密算法实例。算法分为3个步骤：哈希映射、空白填补、字符加密。哈希映射用于制作密码本，负责把明文根据密码本放到密文缓冲区，或根据密码本把明文从密文缓冲区读取出来；空白填补把密文缓冲区空白部分填上随机字符，进一步增加保密级别；字符加密允许用户采用自己特定的加密算法对每个明文字符进行加密。理论分析和实验测试均表明该加/解密算法灵活、便捷，同时可以有效保证用户隐私数据的安全性，允许用户根据实际需求自定制专属自己的独特的保密方法，并且证明在不知道密钥的情况下无法使用蛮力穷举法破解。

关键词: 加密强度可定制, 文本加密, 哈希映射