用C＃实现Des加密和解密-.NET教程,C#语言

using system;

using system.io;

using system.security.cryptography;

namespace vavic

{

/// <summary>

/// security 的摘要说明。

/// </summary>

public class security

{

const string key_64 = "vavicapp";

const string iv_64 = "vavicapp"; //注意了，是8个字符，64位

public security()

{

//

// todo: 在此处添加构造函数逻辑

//

}

public static string encode(string data)

{

byte[] bykey = system.text.asciiencoding.ascii.getbytes(key_64);

byte[] byiv = system.text.asciiencoding.ascii.getbytes(iv_64);

descryptoserviceprovider cryptoprovider = new descryptoserviceprovider();

int i = cryptoprovider.keysize;

memorystream ms = new memorystream();

cryptostream cst = new cryptostream(ms,cryptoprovider.createencryptor(bykey,byiv),cryptostreammode.write);

streamwriter sw = new streamwriter(cst);

sw.write(data);

sw.flush();

cst.flushfinalblock();

sw.flush();

return convert.tobase64string(ms.getbuffer(),0,(int)ms.length);

}

public static string decode(string data)

{

byte[] bykey = system.text.asciiencoding.ascii.getbytes(key_64);

byte[] byiv = system.text.asciiencoding.ascii.getbytes(iv_64);

byte[] byenc;

try

{

byenc = convert.frombase64string(data);

}

catch

{

return null;

}

descryptoserviceprovider cryptoprovider = new descryptoserviceprovider();

memorystream ms = new memorystream(byenc);

cryptostream cst = new cryptostream(ms,cryptoprovider.createdecryptor(bykey,byiv),cryptostreammode.read);

streamreader sr = new streamreader(cst);

return sr.readtoend();

}

}

}