To perform encryption and decryption using Vigenère cipher:

- visit Encryption/Decryption

How to decipher Vigenère cipher:

- Find keylength ( visit Find key length)
- Split the text into parts. Number of parts are equal to the key length. i
^{th}letter goes to (i mod L)^{th}part, where L is the key length ( visit Split text) - For each part perform frequency analysis and find shift value ( visit Frequency analysis)
- Decrypt each part using shift value for that part. ( visit Apply shift)
- Merge decrypted parts in the same order they were splitted. ( visit Merge parts)