r/crypto
Posts
On The Security Of SHA3 (Keccak)
Hello, I am wondering for any information on the security of SHA3 and its sponge function versus older hash functions like MD5, SHA1, SHA2. What makes it more secure? How heavily studied has it been. The sponge function is still newer than the other constructions but its internal state is …
Use of cryptographic primitives
I was reading this [paper](https://dergipark.org.tr/en/download/article-file/4060550) that claims to "combine metaverse with blockchain", but I have a hard time understanding their use of primitives. On page 4 they first generate the key-pairs (not sure which scheme?): https://preview.redd.it/zpkop4rklife1.png?width=672&format=png&auto=webp&s=8cef80acf6bafc73585f06bb71a8a565fea02afb Then the patient uses his/her private key to sign the data, and then the …
The official AES test vectors look incorrect
No way they can be, right? _(Edit: see comments, problem was between chair and keyboard. Thanks!)_ I'm currently writing yet another AES implementation. My goal is to have a bitslice implementation, similar to BearSSL, but with a nicer API. Anyway, right now I'm making a simple, slow, unsafe (variable time) …
Steganographically encode messages with LLMs and Arithmetic Coding
Best beginner cipher to try to solve?
Hi. As title goes, I’m getting into cryptography I’d like to know if there’s any online puzzles or beginner ciphers I can try to solve to start getting into this. Thanks
Offline path to unencrypt a DPAPI encrypted string?
Greetings Crypto Sub! I am dealing with a kind of cryptolocker situation... Not \_that\_ bad, but kinda bad. Data that is encrypted out of my reach: \~8 years of Signal Desktop data (including family photos and much else). How it went beyond reach: In late 2024, Signal Desktop started encrypting …
Caesar Cipher Question
Why does the [dCode.fr](http://dCode.fr) website for Caesar Cipher result in two or more answers for strings I want to decode? Shouldn't there be only one way to shift using key 3? I can't find the answer anywhere. Please help!
Let’s talk about AI and end-to-end encryption
Hybrid key-exchange with PQ-KEM algorithms
I am working on a security-critical tool that uses ECDH to establish shared session keys. I want to reinforce this process by using a PQ-KEM algorithm like Kyber. Right now, I am thinking of achieving this by having two independent key exchanges (one with ECDH keys and one using the …
Probability of randomly generating an EC public key
From what I understand the size of a secp256k1 EC public key is 65 bytes (out of which one is a prefix byte so lets ignore that). The private key is any 256-bit number in [0, N] where N is the order of the curve. So if I have a …