Cryptography Toolkit
Ciphers built, and broken
A collection of cryptographic algorithms and security-protocol implementations built while studying applied cryptography and system security.
Problem
A cryptography course required hands-on cipher implementation — understanding the theory is different from building ciphers correctly and breaking them intelligently.
What was built
A Python toolkit implementing Caesar, Vigenère, RSA and AES, plus cipher-breaking tools that use frequency analysis and AI-assisted scoring to crack substitution ciphers.
System
- Python toolkitShared primitives
- CiphertextSubstitution cipher input
- Caesar · VigenèreClassical ciphers
- Frequency analysisRank candidate keys
- RSA · AESModern ciphers
- Bigram modelScore candidate plaintexts
- OpenAI APIValidate the most likely plaintext
Technical decisions
Build both sides
Classical and modern ciphers are implemented alongside the tools used to attack them.
Layered cracking
Candidate keys are ranked with frequency analysis, refined with a bigram model and validated with the OpenAI API.