Choose between encrypting and decrypting and enter the key and the text below. Only letters (a-z) will be taken into account.

One-time pad, also called OTP, Vernam cipher or the perfect cipher, is the only proven method of cryptography which enables unbreakable encryption, when used correctly. The one-time pad was developed as a paper and pencil method based on the system used in telex communication by Gilbert Vernam in 1917. Later the code was found dating from 1882.