FreeOTP is currently alpha software and is only intended for demonstration and experimentation. It should not be used for real-world cryptography. To encrypt: FreeOTP.exe "The plaintext message" b1fa6ehd53gbcI3NfDjdyGfgL8hts5eHiQ0KbT e To decrypt: FreeOTP.exe "The ciphertext message" b1fa6ehd53gbcI3NfDjdyGfgL8hts5eHiQ0KbT d Notes: 1. Same pad is used to encrypt and decrypt. 2. Pads should be random and destroyed after one use. 3. If a pad is re-used (in whole or in part) the messages can be decrypted by an attacker.