改进的FEA-M实现不当的安全问题
Security Problems with Improper Implementations of Improved FEA-M
摘要：
本文报告了FEA-M（多媒体快速加密算法）的一个改进版本的不正确实现的安全问题。据发现，实现依赖的差分选择明文攻击或其选择密文对应物可以揭示的秘密密钥的密码系统，如果所涉及的（伪）随机过程可以被篡改（例如，通过公共时间服务）。实现相关差分攻击在复杂度上是非常有效的，并且仅需要$O(n^2)$选择明文或密文比特。此外，本文还指出了会话密钥选择中的一个小安全问题。在密码系统的实际实现中，应该小心地避免这些安全问题，或者密码系统必须进一步增强以在这种弱实现下工作。
英文摘要：
This paper reports security problems with improper implementations of an improved version of FEA-M (fast encryption algorithm for multimedia). It is found that an implementation-dependent differential chosen-plaintext attack or its chosen-ciphertext counterpart can reveal the secret key of the cryptosystem, if the involved (pseudo-)random process can be tampered (for example, through a public time service). The implementation-dependent differential attack is very efficient in complexity and needs only $O(n^2)$ chosen plaintext or ciphertext bits. In addition, this paper also points out a minor security problem with the selection of the session key. In real implementations of the cryptosystem, these security problems should be carefully avoided, or the cryptosystem has to be further enhanced to work under such weak implementations.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
