Question 1

What is the difference between these ciphers?

Accepted Answer

Caesar shifts each letter by a fixed number. ROT13 is Caesar with shift 13 (self-inverting). Atbash mirrors the alphabet (A↔Z, B↔Y). Vigenère uses a keyword to vary the shift per letter, making it harder to break.

Question 2

Are these ciphers secure?

Accepted Answer

No, these are classical ciphers meant for learning and fun. They can all be broken easily with modern techniques. For real encryption, use AES, RSA, or other modern cryptographic algorithms.

Question 3

What makes Vigenère different from Caesar?

Accepted Answer

Caesar uses one fixed shift for all letters. Vigenère uses a keyword where each letter determines a different shift. This makes frequency analysis much harder, which is why it was called "le chiffre indéchiffrable" (the indecipherable cipher) for centuries.

Question 4

Why is ROT13 special?

Accepted Answer

ROT13 shifts by exactly 13 positions. Since the alphabet has 26 letters, applying ROT13 twice returns the original text. This makes it self-inverting — the same operation encodes and decodes.

Cipher Encoder & Decoder

📝 Input

🔐 Output

🔠 Alphabet Mapping

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