Linked Questions

Possible Duplicate: Why is h(m||k) insecure? Length-extension allows to append any data to the message while not knowing the secret. Any length-extension explaination one the web considers the ...

If $H(m)$ is a secure hash function, can't we implement a MAC using $H(k\mathbin\Vert m)$? However, it seems the more widely used MACs, such as NMAC and HMAC (both originally defined in Keying hash ...

Consider a common practically-collision-resistant hash function $\mathcal{H}$ (e.g. SHA-1, SHA-256, SHA-512, RIPEMD-160), perhaps based on the Merkle–Damgård construction as are the first three. We ...

I have thought of a system for generating passwords which works as follows: Take the following items: A password, such as williamwallace. A secret 1000 digit ...

Assume both Alice and Bob have a symmetrical key, let's call it $k$. They agree on a cryptographic hash function, let's call it $\mathsf{HASH}$. Now Alice wants to send an authenticated message. She ...

Given that we know that nonce + message + hash(nonce + message + mac-key) all inside the encryption makes it possible to detect if any bits of the message have been ...

Given sha1(pad(A) || pad(B)), where B is known, can I calculate sha1(pad(A))? pad(A) means its length is exactly 1 block (64 bytes for SHA-1) If yes, for which other hash functions it will work too? ...

Proposed Cipher suite (using aes-ecb): ...

I want to use hash function on some data, and part of this data, might be constant for a certain period. The output of the hash function is used as authentication data (MAC). I want to know if there ...

What is the benefit of using HMAC over hash with key suffix? I realize that using key prefix is a bad idea because it allows message extension attacks. When adding key as a suffix such attack ...