Home▸Cryptography▸The One-Time Pad: The Only Provably Unbreakable Cipher

🔐 The One-Time Pad: The Only Provably Unbreakable Cipher

Explore how the one-time pad achieves mathematically perfect secrecy by combining plaintext with a truly random key, and why real-world key reuse (like in the Venona project) destroys that guarantee.

Cryptography3DModerate60 FPS

This simulator shows how a message is transformed into random-looking ciphertext by combining it with a key stream, and how reusing that key stream against a second message reveals recoverable patterns.

🔬 What It Demonstrates

🎮 How to Use

Enter a plaintext message and a key, encrypt it to see the resulting ciphertext, then try reusing the same key on a different message to observe how the perfect secrecy breaks down.

💡 Did You Know?

The Venona project ran for over 30 years, from 1943 to 1980, before US and UK cryptanalysts finished extracting what they could from reused Soviet one-time pad traffic.

⚙ Under the hood

Explore how the one-time pad achieves mathematically perfect secrecy by combining plaintext with a truly random key, and why real-world key reuse (like in the Venona project) destroys that guarantee.

cryptographyone-time-padshannonperfect-secrecyxorvenonainformation-theorycipher

3D · Three.js / WebGL renderer · 60 FPS target · runs fully client-side, no install