Vigenere Cipher Encrypt/Decrypt

Vigenere cipher encrypt/decrypt tool with keyword-based polyalphabetic substitution, live conversion, and one-click copy for classical cryptography lessons and algorithm practice.

Input text

Key settings

A-Z only

Mode

EncryptDecrypt

Only English letters are shifted by the Vigenere cipher. Spaces, numbers, and symbols remain unchanged.

Result

The result will appear here

Documentation

This tool performs Vigenere cipher encryption and decryption with custom keys and live output.

Key Features

Encrypt and decrypt modes
Custom key input with preset keys
Example loading, clear, and copy actions
Fully local browser-side processing

Steps

Enter the text to process.
Provide a key (letters only).
Choose encrypt or decrypt mode.
Review and copy the output.

Use Cases

Classical cipher teaching
Text transformation experiments
Introductory cryptography practice

Notes

Vigenere is a classical cipher and not suitable for modern security use.
Short or predictable keys are easier to break.
Use modern cryptographic protocols for sensitive data.