Decrypt given data previously encoded with des cipher algo. DES (Data Encryption Standard) is a symmetric block cipher that uses a 56-bit key for encryption. Developed by IBM in the 1970s and standardized by NIST in 1977, DES was the most widely used block cipher for decades. DES is considered insecure today due to its short key length, vulnerable to brute-force attacks. It is no longer recommended for use. Our decryption process assumes the IV string is prepended in the encoded string during the encryption process. You can not decrypt and get the correct results if the IV or passphrase mismatch occurs between encryption and decryption process.