UTPB-COSC-4380-Project1-2-Group7

Group 7: Alejandro Sotelo, Bryan Lim, Roman Huerta

📜 Project Overview

This project is a collection of cipher algorithms implemented in Java, designed to encrypt, decrypt, and crack ciphers using various cryptographic techniques. It includes implementations of PolyAlphabetic Cipher, Columnar Transposition Cipher, and a Llama-based Sentence Checker for analyzing decrypted text.

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🚀 Features

• PolyCipher: Implements a polyalphabetic cipher with randomly generated keys and a character mapping matrix.
• ColTransCipher: Implements the Columnar Transposition Cipher, supporting both encryption and decryption with flexible key handling.
• ColumnarTranspositionCracker: A brute-force cracking tool that attempts different key permutations to decrypt a transposition cipher.
• LlamaSentenceChecker: Uses an AI model (Llama 3.3-70B) to analyze decrypted text and identify the most likely meaningful sentence.
• Cipher (Base Class): Provides fundamental alphabet and character manipulation utilities for various ciphers.

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🛠️ Installation & Usage

Prerequisites

Ensure you have:

• Java 11+
• An active internet connection (for API-based decryption evaluation)
• Git (optional, for cloning the repository)

Cloning the Repository

git clone https://github.com/BryanLim0214/UTPB-COSC-4380-Project1-2-Group7.git
cd UTPB-COSC-4380-Project1-2-Group7

Running the Encryption/Decryption

Compile and execute the desired cipher file:

Example: Running PolyCipher

javac src/PolyCipher.java
java src/PolyCipher

Example: Running Columnar Transposition Cracker

javac src/ColumnarTranspositionCracker.java
java src/ColumnarTranspositionCracker

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🔑 Cipher Breakdown

PolyCipher.java

• Generates a random key or accepts a predefined one.
• Creates and stores Beta Matrices for encryption and decryption.
• Encrypts/decrypts text using a matrix-based lookup system.
• Example Usage:

PolyCipher cipher = new PolyCipher(10);
String encrypted = cipher.encrypt("Hello World");
String decrypted = cipher.decrypt(encrypted);

ColTransCipher.java

• Implements Columnar Transposition Cipher with adjustable key formats.
• Supports ascending/descending key order.
• Adds optional padding for structured encryption.
• Example Usage:

ColTransCipher ctc = new ColTransCipher("57183", null, true, false);
String encrypted = ctc.encrypt("Hello World");
String decrypted = ctc.decrypt(encrypted);

ColumnarTranspositionCracker.java

• Attempts to break the Columnar Transposition Cipher by testing different key permutations.
• Uses dictionary-based scoring to determine the best decryption result.
• Example Usage:

javac ColumnarTranspositionCracker.java
java ColumnarTranspositionCracker

LlamaSentenceChecker.java

• Communicates with the OpenRouter AI (Llama-3.3-70B-Instruct).
• Identifies the most meaningful sentence from a list of possible decryptions.
• Example API Usage:

List<String> possibleDecryptions = Arrays.asList("Hello wrld!", "Hello world!", "H3ll0 w0r1d");
String bestSentence = LlamaSentenceChecker.findMostLikelySentence(possibleDecryptions);

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📌 Known Issues

• Columnar Transposition Cracker may take a long time for keys longer than 6 characters due to the exponential growth of permutations.
• LlamaSentenceChecker requires a valid API key from OpenRouter.
• The PolyCipher encryption matrix might generate ambiguous results if two keys are very similar.

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📜 License

This project is open-source and available under the MIT License.

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📬 Contact

For questions or feedback, please open an Issue or contact @BryanLim0214 on GitHub.

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