Vigenere Cipher — Encrypt & Decrypt
Encrypt and decrypt text using the Vigenere polyalphabetic cipher with a keyword. Supports the Latin alphabet.
How to Use the Vigenere Cipher — Encrypt & Decrypt
- Enter or paste your text in the input field.
- The encoded or decoded result appears automatically.
- Copy the output using the copy button.
- Switch between encode and decode modes if available.
Referência Rápida
| De | Para |
|---|---|
| A | 65 (ASCII) |
| Z | 90 (ASCII) |
| a | 97 (ASCII) |
| 0 | 48 (ASCII) |
| Space | 32 (ASCII) |
| @ | 64 (ASCII) |
Casos de Uso
- •Encoding or decoding data for web development projects.
- •Learning about cryptography and different cipher techniques.
- •Preparing encoded content for APIs or data transmission.
- •Solving cipher puzzles, CTF challenges, or educational exercises.
Fórmula
Vigenere cipher: E(i) = (P(i) + K(i mod m)) mod 26, D(i) = (C(i) − K(i mod m)) mod 26, where K is the keyword of length m.
Perguntas Frequentes
What is the Vigenere cipher?
The Vigenere cipher is a polyalphabetic substitution cipher that uses a keyword to shift each letter by a different amount, making it harder to break than the Caesar cipher.
How does the keyword work?
Each letter of the keyword determines the shift for the corresponding plaintext letter. The keyword repeats cyclically for longer messages. For example, keyword 'KEY' applies shifts of 10, 4, 24 repeatedly.
Is the Vigenere cipher secure?
It was considered unbreakable for centuries but can be cracked using Kasiski examination or frequency analysis once the key length is determined. It is not suitable for modern security.
What characters are supported?
This tool processes Latin letters A–Z (case is preserved). Non-letter characters like digits, spaces, and punctuation pass through unchanged.