One Time Pad (OTP) encryption is the only proven unbreakable cryptographic system. It works by combining a randomly generated key pad with the plaintext message. Each letter is encrypted by adding it to the corresponding letter on the pad. To decrypt, the inverse is done by subtracting. OTPs must be used only once and then destroyed to maintain security. Examples are provided of encrypting and decrypting messages using an OTP to demonstrate how it works.