Learn Classical Cryptography

Explore Caesar, Atbash, and Vigenère ciphers to understand the history and principles of cryptography.

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Shifts each letter by 13. Self-inverse — applying it twice returns the original.

Input

Output

Gur dhvpx oebja sbk whzcf bire gur ynml qbt.

Education tips

🎓

These classical ciphers form the foundation of modern cryptography. Atbash (Hebrew) dates to ~500 BCE; Caesar to ~50 BCE; Vigenère to the 16th century.

💡

Caesar and Atbash are monoalphabetic — each letter always maps to the same output. Vigenère is polyalphabetic — the same letter maps to different outputs depending on position.

🔐

The Vigenère cipher was called "le chiffre indéchiffrable" (the indecipherable cipher) for centuries until Charles Babbage cracked it in 1854.

🧩

Try encoding the same message with all four ciphers and compare. The Vigenère output looks most random because the key varies — this demonstrates why key length matters.