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.
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Hash-based nullifier without an elliptic-curve key tree: what carries unlinkability, and how do we bind spend authority post-quantum?
We are building the shielded pool of a post-quantum transaction layer. A note is committed as $c_m = H(v \parallel r)$ (value $v$, trapdoor $r$), commitments accumulate in a Merkle tree, and to spend ...
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Is a commit-reveal hash binding sufficient to prevent adaptive forgeries in a Stochastic Matrix Audit over F_p?
I am designing a verifiable computation protocol where a prover multiplies two large matrices $A$ and $B$, resulting in $C$. To verify $AB = C$ without recomputing in $O(n^3)$ time, I am using ...
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Novel stream cipher concept: secret-dependent offset centralization — prior art or interesting idea?
I've designed an experimental stream cipher called LabyX built around one core idea I haven't found in the published literature:
The keystream is larger than the plaintext, and the plaintext is hidden ...
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Are there any hash functions heavily-optimized for modern GPUs?
There is plenty of research into hash functions, KDFs, and PoW constructions designed to be GPU-unfriendly, but I'm looking for the opposite: A hash function designed to be fast on GPUs when performed ...
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A natural hybrid hash function based on DLP and GapSVP
Let $E$ be an elliptic curve over a finite field $\mathbb{F}_q$ for which $\mathcal{O}$ denotes the zero point. For simplicity, assume that the order $r$ of the group $E(\mathbb{F}_q)$ is prime. One ...
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Security of ECDSA with external message hashing
In the definition of ECDSA, Signing and Verifying accept a message $M$ as an octet string of essentially arbitrary size. The only operation performed directly on $M$ is computing it's hash $H$, an ...
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PQC on resource poor hardware
I have hardware with like 1400kB RAM and would like to secure its firmware update. For that, my idea was to store the PQC MLDSA key, more like the hash of the key, on the OTP fuses. Then, I would ...
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Are there any examples of an efficient unkeyed hermetic permutation other than Keccak-$f$?
I am looking for an example of an efficient cryptographic permutation $P$ whose author(s) explicitly claimed that $P$ was designed to be hermetic.
Designers of the Sparkle permutation explicitly claim ...
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Is sha256(api_key ∥ user_id) mod 64 sufficient for cryptographic user isolation in a partitioned inference engine?
I'm designing a partitioned inference engine where each user is assigned to an isolated partition using:
partition = sha256(api_key ∥ user_id) mod 64
The goals are:
No shared cache between users
No ...
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Is message-bound key derivation a known cryptographic construction, and has it been analyzed as a MAC alternative?
I was exploring why AWS uses HMAC-SHA256 for request signing (SigV4) rather than plain SHA-256, and specifically why the length extension vulnerability in raw SHA-256 can't be worked around at the ...
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What practical power does an attacker gain if a hash function is not strong but weak collision-resistant?
I am trying to understand the practical implications of a hash function that is weak collision resistant, but not strong collision resistant.
That is, an attacker
can efficiently find some pair of ...
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Is it safe to repurpose some part or all of the IV for a tweak in a Davies–Meyer compression function hash?
When using a Davies–Meyer single-block-length compression function as a short input hash function: $$\mathsf{H}(x) = \mathsf{IV} \oplus \mathsf{Enc}(x, IV)$$
Is it safe to repurpose some part or all ...
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Can multiple hash functions be combined to give rise to a more secure hash function?
If performance is of no concern and the goal is to create an overkill hash function without resorting to altering the internals (e.g., rounds) of existing standards (e.g., SHA-2, SHA-3), would the ...
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Do I have the right understanding of Universal Hash, crypto hash, and Random Oracle?
Universal Hash: It involves uniform random sampling from a keyed function family. Therefore, it possesses collision resistance but does not require preimage resistance or PRF security. It is a ...
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Can the reduced round permutation of Turboshake be used to create a duplex function?
The Keccak team introduced a SHAKE hash variant called TURBOSHAKE which is based on the original Keccak-F1600 permutation but with a reduced round count of 12 from 24.
My question is : Can this ...
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