Encrypt or decrypt text using the Vigenère polyalphabetic cipher. Vigenère Cipher is a free online tool from the ToolsRift Encoders & Decoders collection. It runs entirely in your browser — nothing to install, no signup, and your data never leaves your device.
A series of Caesar ciphers with different shifts determined by the letters of a repeating keyword.
Much stronger than Caesar but still breakable via Kasiski examination for long ciphertexts. Not suitable for modern security.
A single word or phrase using only letters (A—Z). Longer keys are harder to crack.