Exponential Brute-Force Complexity of A Permutation Based Stream Cipher
This paper introduces a permutation generation mechanism based on a shared secret key. The generated permutation vectors are used as encryption keys in a stream ciphering cryptosystem. The authors investigated various types of attacks on the known stream cipher RC4 and patched most of its loopholes, especially biased-byte and state-related attacks. Unique to their approach, they prove mathematically that the complexity of brute-forcing such a system is (2n), where n is the key size in bytes. This paper also presents a complete security model using permutation-based encryption, in order to handle privacy. In addition, their approach achieved higher performance than that of existing peer techniques, while maintaining solid security.