# All Questions

149 views

### Length-preserving all-or-nothing transform

Is there any known way to construct a length-preserving all-or-nothing transform? In other words, a secure all-or-nothing transform where the length of the output is the same as the length of the ...
505 views

### Choose a random number that is different from a bunch of other secret numbers

I'm looking for an algorithm where n participants each have a different secret number between $[0..x]$ (and where $x$ is known) and where the participants then select randomly another, non-secret, ...
294 views

### SHA1 collision event probability after n iterations

There are String1 and String2 - some variables-strings. The probability of collision for different ...
553 views

### Is HMAC needed for a SHA-3 based MAC?

HMAC does nested hashing in order to prevent Length Extension Attacks. Given that you use the SHA-3 hash (which is resistant against length extension attacks), would you still need to go through that ...
182 views

### SHA1 multipart calculation

Is it possible to combine SHA1 digest values to get the SHA1 of the concatenated parts ? I know the "S1" SHA1 of "part 1" and the "S2" SHA1 of the "part 2" and I would like to know the SHA1 of the "...
161 views

### Non-commutitive and nonassociative algebraic structures in cryptography

Are there any cryptographic algorithms or primitives that have been developed and studied that make use of non-commutative or non-associative algebraic structures such as quaternion integers or ...