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The accepted answer is completely wrong. There is a simple way to convert a stream cipher into a block cipher. In pact, it works for any PRF, regardless of if it is reversible or not. This presentation perfectly covers how to use a PRG such as a stream cipher to construct a block cipher. Basically, you use the stream cipher in the following manner: Take ...


Most stream ciphers (the so-called synchronous ones) work by producing a key stream from a key, which is then XORed with the plaintext to produce a cipher text. It is important that the same key (or, equivalently, the same part of a keystream) is not used twice, as then it is (more or less) easy to recover the plaintext. If you use only a small part of that ...


This [Carter-Wegman] MAC is not, in general, secure in the quantum setting This is true; however we need to ask "what is this setting, and is it a realistic one?" This setting is one where the adversary can ask queries that are composed of a superposition of quantum states, and the oracle returns the superposition of the answers. In other words, the ...


Actually, a post-quantum security is truly achieveable in a cipher-combo only. So - take a look at AES-finalist-candidates, like Serpent, and use it too or just it, but in 512 bit keys. Here is the starting point for you : enter link description here

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