Complexity Measures of Cryptographically Secure Boolean Functions
نویسندگان
چکیده
In stream cipher cryptography a pseudorandom sequence of bits of length equal to the message length is generated. This sequence is then bitwise XORed (addition modulo 2) with the message sequence and the resulting sequence is transmitted. At the receiving end, deciphering is done by generating the same pseudorandom sequence and bitwise XORing the cipher bits with the random bits. The seed of the pseudorandom bit generator is obtained from the secret key. For some recent proposals of stream ciphers refer the eSTREAM Project (The ECRYPT Stream Cipher Project). Linear (non-linear) Feedback Shift Registers (LFSRs) and Boolean functions are important building blocks for stream cipher systems. A standard model of stream cipher by Siegenthaler (1984, 1985) combines the outputs of several independent LFSR sequences using a nonlinear Boolean function to produce the keystream. Design and analysis of stream ciphers was kept ABSTRACT
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