Questions tagged [hash]
A cryptographic hash algorithm is a function which takes a variable size input and produces a fixed size output. The algorithm makes it difficult to find two inputs with the same output or reconstruct the input from the output.
3,116 questions
4 votes
0 answers
92 views
Hash function with lightweight ZKP of a preimage
For a standard hash function $H$ like SHA-256, one can choose a secret message $M$, compute and publish $h=H(M)$, then prove knowledge of the preimage $M$ in zero knowledge [that is without disclosing ...
- 151k
1 vote
0 answers
61 views
How to determine the algorithm used to generate a 48-byte header for encrypted files? [closed]
I am engaged in the translation of encrypted files. I have several files encrypted in the same way. The files consist of two parts: 48 byte header example - ...
- 11
4 votes
2 answers
128 views
Security strength of DRBG
The security strength of Hash based DRBG (Hash_DRBG and HMAC_DRBG) confuses me. Which property of Hash determines the security strength of DRBG? For example, which SHA2 algorithms can be used to ...
- 41
6 votes
2 answers
1k views
Is it insecure to use a hash with secret salt instead of a signature?
I have a chunk of data that I need to round-trip through a service that I don't trust, and I want to make sure the data hasn't been tampered with in-transit. I have limited memory and limited storage, ...
- 163
2 votes
1 answer
174 views
Is omitting the first output in the squeezing phase of a sponge a security risk?
I recently saw a specification of a hash function, which is based on a sponge. The hash function produces a $128$ bit message digest $H(X)$. Let's assume that $S$ is the final state of the absorbing ...
- 168
1 vote
0 answers
60 views
How to locate and audit the Layer-3 scrambling (masking/hash/PRNG) function and seed in Pret-a-voter or similar secure voting system source code? [closed]
I am performing a cryptographic audit and reconstruction for a secure voting system inspired by Pret-a-voter. I currently have access to deterministic PRF mapping (Layer-1) and modulo/checksum filter (...
- 11
0 votes
1 answer
57 views
Security impact of partial key knowledge for stateful hash-based signatures
Let us consider a stateful hash-based signature scheme (e.g. LMS or XMSS) with an $n$-bit hash function where each signature is composed of $x$ hash chains. Assuming an attacker has knowledge of $y &...
- 3,007
1 vote
1 answer
123 views
Does the leftover hash lemma imply or require hashing with random salts?
As I understand the leftover hash lemma: I pick a hash function $h$ at random from an $2$-universal family of hash functions. I pick a random string $s$, and then $(h(x,s),s)$ is statistically close ...
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