ctf-crypto

Decrypt classical and modern ciphers for CTF cryptographic challenges.

12|Updated Jun 9, 2026
One-click install
npx skills add https://github.com/nimosocute/ctf-codex-toolkit --skill ctf-crypto-nimosocute
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: ctf-crypto
Source: https://github.com/nimosocute/ctf-codex-toolkit/tree/main/payload/home-codex/skills/ctf-crypto
Command: npx skills add https://github.com/nimosocute/ctf-codex-toolkit --skill ctf-crypto-nimosocute

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires pycryptodome, z3-solver, sympy, gmpy2, hashpumpy, fpylll, and includes scripts (resource) and references (resource) and assets (resource) components.

What problem does it solve?

This Skill provides a comprehensive set of cryptography attack techniques, empowering users to solve various cryptographic challenges in Capture The Flag (CTF) competitions.

Core Features & Use Cases

  • Classic Ciphers: Decryption techniques for historical ciphers like Vigenere, Atbash, and XOR.
  • Modern Ciphers: Analysis and attacks on modern ciphers like AES, RSA, and ECC.
  • Lattice/LWE Attacks: Solving lattice-based problems and Learning With Errors (LWE) challenges.
  • Other Attacks: Techniques for attacking PRNGs, ZKP, and advanced mathematical attacks like isogenies and number theory.
  • Use Case: A CTF participant can use this Skill to understand and solve complex cryptographic challenges, such as breaking encryption, finding vulnerabilities in cryptographic schemes, or performing cryptographic attacks.

Quick Start

Use the ctf-crypto skill to analyze the ciphertext provided in 'encrypted_flag.txt'.

Frequently Asked Questions about ctf-crypto

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I solve cryptographic challenges in CTF competitions?

To solve cryptographic CTF challenges, you need dedicated attack techniques for classical and modern ciphers. This Skill provides decryption methods for AES, RSA, and ECC, alongside lattice-based and LWE attack strategies to break encryption schemes.

What techniques are needed to break modern ciphers like RSA and AES?

Breaking modern ciphers like RSA and AES requires mathematical analysis and vulnerability identification in the cryptographic scheme. This Skill provides specific attack techniques utilizing libraries like pycryptodome, sympy, and gmpy2 to perform advanced cryptanalysis.

How do I perform lattice-based attacks for Learning With Errors challenges?

Performing lattice-based attacks for Learning With Errors (LWE) challenges requires reducing lattice problems using specialized algorithms. This Skill implements LWE attack techniques leveraging the fpylll library to solve complex lattice-based cryptographic constructions.

Do I need to install z3-solver and pycryptodome to attack PRNGs and classical ciphers?

Yes, attacking PRNGs and decrypting classical ciphers requires installing dependencies like z3-solver and pycryptodome. These libraries enable the mathematical modeling, constraint solving, and cryptographic operations necessary to execute the provided attack scripts.

Can I use this to find vulnerabilities in cryptographic schemes and Advanced mathematical attacks like isogenies?

Yes, you can analyze cryptographic schemes for vulnerabilities using advanced mathematical attacks including isogenies and number theory. The Skill incorporates techniques to attack PRNGs, ZKP, and perform mathematical cryptanalysis using z3-solver and sympy.

What's the best way to analyze an encrypted flag file for a CTF crypto challenge?

The best way to analyze an encrypted flag file is to apply targeted decryption techniques based on the identified cipher type. You can use this Skill's scripts to process the ciphertext, automatically applying classical decryption, lattice attacks, or modern cipher analysis to recover the flag.