Unlock the secrets of secure communication with our Vigenère Cipher Calculator. Easily encrypt your plain text or decrypt cipher text using a chosen keyword. This powerful online tool brings a classic cryptographic method to your fingertips, ensuring your messages remain private and understood only by intended recipients. Perfect for learning, security, or practical use.
Formula:
The Vigenère Cipher uses a polyalphabetic substitution based on a keyword. Each letter of the plaintext is shifted by a different amount determined by the corresponding letter of the keyword.
For a letter at position i:
- Encryption:
Ci = (Pi + Ki) mod 26 - Decryption:
Pi = (Ci - Ki + 26) mod 26
Where:
Pi: Numerical value (0-25) of the i-th plaintext letter (A=0, B=1, ..., Z=25)Ki: Numerical value (0-25) of the i-th keyword letter (repeated to match plaintext length)Ci: Numerical value (0-25) of the i-th ciphertext lettermod 26: Modulo operation to wrap around the alphabet