# Tag Info

1

As already discussed by @fgrieu in his answer and myself in the comments of your question and his answer, the standard notion of security of digital signature schemes, namely (strong) existential unforgeability under adaptively chosen message attacks (UF-CMA), does not cover the case you are concerned about. At least for hash-then-sign signatures built ...

4

By a generic attack we also understand an attack that with minimal corrections would apply to every block cipher. For example, suppose you have a (plaintext,ciphertext) pair and test keys by exhaustive search: you apply the keyed cipher $E_K$ to plaintext $P$ for every $K$ and check if you get ciphertext $C$ in response. Quite often, the ciphertext bits ...

3

As explained in a comment: A generic attack is one that works against all block-ciphers (with a given block and key size), without consideration about the structure of the block-cipher. One generic attack for a block cipher of a given block size $b$ bits builds a dictionary of input/output pairs (e.g. from past plaintext/ciphertext), for a fixed key. When ...

0

The parameter $k$ appeared in the definitions of hash functions, since many properties are difficult to formulate for a single concrete hash function. For instance, what would it mean that SHA-256 is collision resistant? Clearly, there are values that collide, and there exists a very short algorithm that outputs a collision in a small constant time. To ...

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