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Classical Ciphers

Caesar cipher, ROT13, Vigenere, and historical cipher tools

ROT13 Encoder

Encode text with ROT13 or ROT47 instantly. ROT13 is self-inverting — encoding and decoding are the same operation. Used for spoilers and puzzle forums.

ROT13 Decoder

Decode ROT13 or ROT47 text instantly. ROT13 is self-inverting — apply it once to encode, once more to decode. Used for spoilers and puzzles on Reddit, Usenet.

Caesar Cipher Encoder

Encode text with a Caesar cipher shift of 1–25. Classic shift-3 Julius Caesar cipher, real-time output, brute-force mode. Nothing uploaded.

Caesar Cipher Decoder

Decode Caesar cipher text with any shift 1–25, or brute-force all 25 shifts instantly. Historically used by Julius Caesar with shift 3.

Encrypt and decrypt messages using classical and historical cipher methods including Caesar cipher, ROT13, Vigenere, Atbash, and more. Explore cryptography fundamentals, learn how historical encryption worked, and decode ciphertexts. All cipher operations execute locally in your browser for instant results.