Teaching & Overview

What is the Cipher Corpus?

• A curated library of classical ciphertext challenges with known plaintexts and metadata
• Includes synthetic and historical examples, multilingual and noisy records
• Designed for learning, teaching, and benchmarking cryptanalysis tools

How to Use the Corpus

• Practice codebreaking in Challenge Mode (solution hidden)
• Study metadata and solutions in Known Corpus Mode
• Download the dataset for research or tool development
• Contribute new records following the contribution guide

For Educators

• Use real and synthetic ciphers to teach cryptanalysis concepts
• Assign challenges by difficulty, cipher type, or language
• Demonstrate solver benchmarking and reproducibility

For Tool Builders

• Test solvers on a reproducible, versioned benchmark
• Use the schema for integration and validation
• Publish results with reproducibility receipts

Engine Accuracy & Provenance

Every interactive cipher engine in the museum is verified against published known-answer test vectors, not just internal roundtrips:

• Bruce Schneier's four published Solitaire/Pontifex vectors (including SOLITAIRE / CRYPTONOMICON → KIRAK SFJAN)
• Wikipedia and Practical Cryptography known answers for Playfair, Hill, Rail Fence, Bifid, Nihilist, and others
• A 100,000+-record corpus with a 100% decode-roundtrip validation pass on every release
• An automated suite of 9,000+ checks (engines, demos, accessibility, structure) run on every change

Where an engine follows a specific historical convention (for example, the Four-square exhibit uses the ACA 25-letter I/J-merged alphabet rather than Wikipedia's Q-omitted example), the exhibit page documents that choice. The test suites are public in the GitHub repository if you want to inspect or re-run them.

Resources

• Corpus Browser
• Schema

Contact & Feedback

Open an issue on GitHub with questions, suggestions, or contributions.