Differential Cryptanalysis of T-Function Based Stream Cipher TSC-4
نویسندگان
چکیده
TSC-4 is a T-function based stream cipher with 80-bit key, and proposed as a candidate for ECRYPT eStream project. In this paper, we introduce a differential method to analyze TSC-4. Our attack is based on the vulnerable differential characteristics in the state initialization of TSC-4, and for the chosen IV pairs, the differential probability is up to 2−15.40 in the case of weak keys. We show that there are about 2 weak keys among the total 2 keys. To recover 8 bits of a weak key needs about 2 chosen IV pairs. After that, we can search the other 72 key bits by an exhaustive attack.
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