Vigenère Cipher Tool
Encrypt and decrypt text using the Vigenère cipher, a classic polyalphabetic substitution cipher.
Vigenère Cipher
Enter your text and key below to encrypt or decrypt using the Vigenère cipher.
About Vigenère Cipher
The Vigenère cipher is a method of encrypting alphabetic text using a series of interwoven Caesar ciphers based on the letters of a keyword.
How it works: Each letter in the plaintext is shifted by a number of positions in the alphabet based on the corresponding letter in the key.
Security: While more secure than simple substitution ciphers, Vigenère cipher is not secure by modern standards and is mainly used for educational purposes.
Key requirements: The key should contain only letters (A-Z). Numbers and special characters are automatically removed.