DES - Data Encryption Standard demo

This program was written only for demonstration of the DES encryption and decryption example from the book of "Cryptography Theory and Practice", Douglas R. Stinson, but could be easily modified to accept real text ... In this Demo you can use only Hexadecimal Plaintext and Key no less then 16 digits (64 bits), more then 16 digits will be ignored ... Output: Cipher 16 digit (64 bits) long and vice versa. Program was written in VB6. The only OCX was used is Microsoft Rich TextBox Control 6.0 This is not ready to send messages DES program. You can start by entering 16 digit long Plaintext and Key, or you can accept the pre-filled example data from the book. Then follow the buttons' order from the top to the bottom in the Encryption Steps frame. When got your cipher follow the buttons' order from the top to the bottom in the Decryption Steps frame. You can view the computation process of encryption and decryption on the History form. Should be simple enough if you're familiar with DES algorithm ...