一个书中的实例，Delphi双重DES加密算法演示源程序，源码在D7下直接编译就行了，可以顺利运行。源码主要演示如何在Delphi环境下实现双重的DES加密，允许输入明文的情况下，可输入两个DES密钥，可输入密文后实现加密功能，双重DES 要比单一的DES加密更安全，不容易被破解。

-An example of the book, Delphi double DES encryption algorithm demo source code, source code in D7 compiler directly on the line, can run smoothly. Main source demonstrates how to implement the Delphi environment double DES encryption, under the circumstances expressly permitted input, you can enter two DES keys, encryption feature to enter the ciphertext, double DES than single DES encryption is more secure, not easy to be cracked.