自己写的有关VC连接SQL SERVER，MD5加密，打印文件，显示图片的类，绝对能用。-VC wrote on their own to connect SQL SERVER, MD5 encryption, print documents to show the picture of class, absolutely can.

C#二维码编码 解码程序，并附带MD5加密功能-C#-dimensional code codec procedures and functions with MD5 encryption

包括两个部分：数字签名和签名认证。密钥采用des加密。通过md5获取数字摘要。然后用rsa签名/认证。-Consists of two parts: digital signature and signature authentication. Key using des encryption. Through the md5 access to digital paper. Then use the rsa signature/certification.