Streaming cryptosystems
Laboratory work II on the Theory of Information. Teacher: Boltak S.V.
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The basic idea of streaming cryptosystems is to encrypt the source
text M using a cryptographic key K, whose length is equal to the length of the text.
Each ciphertext bit C i is a function of the corresponding bits of the source text.
and key stream.
The symbol ⊕ denotes the addition operation "EXCLUSIVE-OR". Due to the linear properties of this operation when encrypting and decrypting the same key stream K is used. Obviously, in this case the length K must be equal to the length of the transmitted message. However, key exchange large size is often impossible. Therefore, in practice, to form keystream use pseudo-random sequence generators