Cryptanalysis Toolkit Documentation

This suite comprises four interconnected projects for analyzing and cracking classical ciphers. Below is a detailed breakdown of each component:

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1. ADFGVX Cracker (C++)

Purpose: Crack the ADFGVX cipher using parallel permutation testing and frequency analysis.
Key Features:

• Multi-threaded Permutation Analysis: Tests transposition keys of lengths 6–10 simultaneously.

• Index of Coincidence (IC) Scoring: Ranks decrypted texts by closeness to English IC (0.0667).

• Interactive Substitution: Users manually adjust bigram-to-character mappings for refined decryption.

• Frequency Mapping: Uses bigram frequencies to guess substitutions.

Code Structure:

• Cracker.h: Manages threads, permutations, and IC calculations.

• Cipher.cpp: Implements ADFGVX encryption logic (for validation).

• CMakeLists.txt: Build configuration.

Usage:

./ADFGVXCrackerV2  # Starts interactive cracking session

Output: Displays candidate keys and allows real-time substitution adjustments.

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2. Playfair Cracker (Java)

Purpose: Decrypt Playfair ciphertexts using simulated annealing and quadgram scoring.
Key Features:

• Simulated Annealing: Iteratively refines decryption keys with temperature decay.

• Quadgram Scoring: Evaluates text likelihood using precomputed frequency data (quadgram.h).

• Key Manipulation: Dynamically swaps rows, columns, or characters to explore the key space.

Code Structure:

• Cracker.java: Implements annealing logic and key manipulation.

• Main.java: Hardcodes ciphertext and initializes cracking.

Usage:

java PlayfairMain  # Starts automated key optimization

Output: Logs high-scoring keys and decrypted text snippets.

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3. Transposition-Vigenère Cracker (Java)

Purpose: Attack combined Transposition + Vigenère ciphers.
Key Features:

• Permutation Generation: Tests all possible transposition keys (O(n!) complexity).

• Layered Decryption: First cracks transposition, then Vigenère using IC filtering (≥0.06).

• Multi-threading: Parallelizes work across key lengths 6–10.

Code Structure:

• Cracking.java: Derives Vigenère keys via frequency analysis.

• Utils.java: Handles text rearrangement, IC calculation, and permutations.

• Executer.java: Thread logic for parallel execution.

Usage:

java Main  # Starts multi-threaded cracking

Output: Prints valid transposition/Vigenère key pairs and decrypted plaintext.

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4. Enigma Machine Simulator & Cracker (Python)

Purpose: Simulate an Enigma machine and provide foundational tools for crib analysis.
Key Features:

• Enigma Components:

  • rotor.py: Models rotors with configurable wirings and rotation.

  • reflector.py: Implements fixed reflector permutations.

  • plugboard.py: Handles letter swaps.

• Crib Analysis (WIP): Uses networkx to map plaintext-ciphertext relationships.

Code Structure:

• enigma.py: Combines components to encrypt/decrypt messages.

• cracker.py: Early-stage graph-based analysis (non-functional for full decryption).

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Limitations

1. Enigma Cracker: Not finished. Only simulates encryption; crib analysis is incomplete.

2. Performance: Transposition permutation tests become impractical beyond key length 10.

3. Interoperability: Components are language-specific (C++/Java/Python).

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Note: This project was created for the University of Antwerp's Code Theory class. Real-world ciphers require more advanced techniques.

Learning purposes only.