Menu

Individual skill

cryptography

0upvotes

Cryptanalysis techniques — lattice attacks, padding oracles, weak-RNG exploitation, signature forgery, secret-sharing recovery.

skills/cryptography/SKILL.md

Read pinned source

Source commit 95fdc128af4ca1ae16b3226f9430f1bad97b0656

What was checked

Matches the observed repository HEAD
Yes
Scanner rules are current
Yes
Repository scan complete
No
Skill scan complete
No
Observed behavior
Network or broad shell
Last checked
Nov 10, 2026

These are observations at the recorded commit, not a guarantee of safety. Review the source before running it.

Install this skill

Choose an agent in your Stack or copy a command below. Commands fetch the pinned commit and copy only this skill directory. Existing destinations are refused. Copying a command does not install anything.

An install command is unavailable: current rules, complete repository and skill scans, an eligible behavior level and a permitted license are required.

Repository context

Repository stars (not skill ratings)
613
Repository last updated
Jul 29, 2026
License
MIT

Observed agent integration: No specific integration evidence. Standard SKILL.md installation does not imply verified compatibility.

Files and excerpt

File metadata and permitted, redacted excerpts come from the recorded scan. Source links are pinned to that commit.

Browse files
Read excerpt

# Cryptography

## Scope

Practical cryptanalysis for CTF and pentest engagements: identifying when a cryptographic primitive's structure (custom hash, partial leaks, related primes, bad RNG, weak modes) admits a faster-than-brute-force solver, then implementing that solver in pure Python where possible. Covers RSA-style algebraic factoring, lattice/AGCD recovery, GF(2) linear collapse of "complicated-looking" custom ciphers, smooth-order DLP, differential fault attacks, and Shamir-style secret-sharing recovery over non-prime moduli. Always read source first to detect linearity/algebraic structure before reaching for SageMath or symbolic solvers.

## When to use

- A challenge or target ships **custom crypto** (custom hash, custom block cipher, hand-rolled key derivation) and you need to look for affine / GF(2)-linear collapse.
- RSA-style primitives with **structured primes** (`p = a·r + b`, `phi(n)` perfect square, multi-prime hint files, common factors).
- A service exposes a **chosen-ciphertext / chosen-input oracle** and you suspect padding-oracle, smooth-order DLP, or Bleichenbacher-style recovery.
- AES with **fault injection** (correct + faulty ciphertext for the same key — Piret-Quisquater DFA).
- Shamir secret sharing or threshold schemes with non-prime moduli (2-adic recovery via Lagrange interpolation with valuation tracking).
Back to top