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I would be inclined not to even call it a stream cipher. If I had to give it a name, it would be reactive encryption algorithm or perhaps forward reactive encryption algorithm. This name implies what it does, which is react to the plaintext in some way going forward, rather than simply encrypting it. You can build something like this very easily using the ...


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Logically I think that should also be a synchronous stream cipher. The word refers to the fact that the keystreams must be synchronized between the encrypter and the decrypter to allow decoding. With anything other than a self-synchronizing cipher that is the case. However, that does not mesh with existing usage. You will find many texts (example) saying ...


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Important note: One-time pad does not "not give any information about the content of the message". This is a fallacy. It still does reveal information. For example, simply knowing that there exists an exchanged message does tell us some information. If the assumptions of the one-time pad are satisfied, what we will have is an encryption method that ...


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The other answer already explains that what you are looking for is a message authentication code, but did not show a clear attack against your construction. At the very least it seems to be vulnerable to length-extension type attacks, like the keyed hash mentioned: Take the output for some known message, where the length of the key x and message v is ...


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If I understood your question correctly, you want a message authentication code (MAC). The "hidden input" is usually called key and the "visible input" is just the message. The output of the MAC is called tag (or also MAC). The main security goal for MACs is resistance against forgery: It should be computationally infeasible for an attacker who does not ...


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Actually, it turned out that scrypt was not as good as initially advertised under all conditions. Scrypt was designed to support the specific case of password-based key derivation for full harddisk encryption. Basically, you type your password when the machine boots up (or awakes from hibernation). This is a context where the following apply: The password ...


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I guess the honest answer is nobody can know for sure, however: There's a general rule of thumb in cryptography, that once there was been wide rewards for breaking an algorithm (be it a hash function, a cipher or in this case a key deviation function) but nobody has come to close the breaking it, then we are in the "safest period". Scrypt is almost ...



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