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I have looked at some attacks on RC4 and be curious if some of them can be applied to Spritz as well. Does anybody else has analysed Spritz so far? Or is it far too early for results against Spritz? No third party analysis. Probably way too early. (Even the paper you linked is unpublished.) The answer may of course change any time. From the ...


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To answer the question "why does a block cipher use a Mode of Operation", we need to first examine the question "what is a block cipher?" A block cipher is a keyed operation that converts a string of N bits to a string of N bits (where N is usually fixed by the block cipher; for AES, N=128), in a way that, without the key, looks like a random permutation, ...


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I will try to not directly answer your question, but this exercise is so simple that it gets hard to help you without doing that. You are going to use a symmetric cipher (One-Time Pad - OTP), thus your initial step is to compute your key. This is given by the execution of the LFSR as you described, until a key-stream of the length of the message is ...


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For any typical stream cipher (including block ciphers in streaming modes like CBC / CFB / OFB / CTR), the time needed to encrypt a message consists of two parts: the time needed to set up the cipher, which is approximately constant, and the time needed to encrypt a chunk of the message (also approximately constant), multiplied by the number of chunks in ...


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The way I picture it, a pseudorandom number generator (PRNG) has a box of bytes called "internal state". Seeding the PRNG sets that box of bytes to some deterministic function of the seed. Every time you ask the PRNG for another number, the PRNG "stirs the pot" to some new state -- using a deterministic function of the previous state. The PRNG also ...



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