Vigenere Cipher Encoder Decoder
Encrypt or decrypt text using the classic Vigenere polyalphabetic cipher with keyword-based substitution. Encode messages with repeating keyword patterns for stronger classical encryption.
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Readme
What is the Vigenere cipher?
The Vigenere cipher is a polyalphabetic substitution scheme that shifts letters according to a repeating keyword. Each character of the key selects a different Caesar shift, making the pattern far harder to spot than a single fixed rotation. Historically it was considered "unbreakable" until analysts used frequency analysis on repeated key cycles, which is why it still serves as a foundational lesson in classical cryptography.
Tool description
Encode or decode passages with a customizable keyword using the caesar-salad implementation of the Vigenere cipher. Letters rotate based on the key while punctuation, digits, and spacing remain untouched so the output stays readable.
Features
- Keyword input that accepts only letters and normalizes them automatically
- Instant encryption and decryption powered by the caesar-salad Vigenere engine
- Preserves whitespace, numbers, and punctuation while rotating alphabetic characters