原文: 一个java的DES加解密类转换成C#

一个java的des加密解密代码如下：

//package com.visionsky.util;

import java.security.*;
//import java.util.regex.Pattern;
//import java.util.Hashtable;
import javax.crypto.*;
import javax.crypto.spec.*;

import sun.misc.*;

/**
 * des加密解密
 */
public class DESPlus {
    private static String strDefaultKey = "PLFP"; //默认密钥

    private static final byte[] iv = {0x12, 0x34, 0x56, 0x78, (byte) 0x90, (byte) 0xab, (byte) 0xcd, (byte) 0xef};//des 向量

    private static BASE64Encoder enc = new BASE64Encoder();//将byte[]转换成String

    private static BASE64Decoder dec = new BASE64Decoder(); //将String转换成byte[]

    /**
     * 加密字节数组
     *
     * @param arrB
     *            需加密的字节数组
     * @param key
     *            密钥
     * @return 加密后的字节数组
     * @throws Exception
     */
    public static byte[] encrypt(byte[] arrB, String key) throws Exception {
        DESKeySpec desKeySpec = new DESKeySpec(key.getBytes());

        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        SecretKey secretKey = keyFactory.generateSecret(desKeySpec);
        IvParameterSpec ivp = new IvParameterSpec(DESPlus.iv);

        Cipher encryptCipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
        encryptCipher.init(Cipher.ENCRYPT_MODE, secretKey, ivp);

        return encryptCipher.doFinal(arrB);
    }

    /**
     * 加密字符串
     *
     * @param xml
     *            需加密的字符串
     * @param key
     *            密钥
     * @return 加密后的字符串
     * @throws Exception
     */
    public static String encrypt(String xml, String key) throws Exception {
        //return DESPlus.enc.encode(encrypt(xml.getBytes(), key));
	return new String(encrypt(xml.getBytes(), key)); 
    }

    /**
     * 使用默认公钥加密字符串
     * @param xml 需加密的字符串
     * @return 加密后的字符串
     * @throws Exception
     */
    public static String encrypt(String xml) throws Exception {
        return encrypt(xml, strDefaultKey);
    }

    /**
     * 解密字节数组
     *
     * @param arrB
     *            需解密的字节数组
     * @param key
     *            密钥
     * @return 解密后的字节数组
     * @throws Exception
     */
    public static byte[] decrypt(byte[] arrB, String key) throws Exception {
        DESKeySpec desKeySpec = new DESKeySpec(key.getBytes());

        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
        SecretKey secretKey = keyFactory.generateSecret(desKeySpec);
        IvParameterSpec ivp = new IvParameterSpec(DESPlus.iv);

        Cipher decryptCipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
        decryptCipher.init(Cipher.DECRYPT_MODE, secretKey, ivp);

        return decryptCipher.doFinal(arrB);
    }

    /**
     * 解密字符串
     *
     * @param xml
     *            需解密的字符串
     * @param key
     *            密钥
     * @return 解密后的字符串
     * @throws Exception
     */
    public static String decrypt(String xml, String key) throws Exception {
        return new String(decrypt(DESPlus.dec.decodeBuffer(xml), key));
    }

    /**
     * 使用默认公钥解密字符串
     * @param xml 需解密的字符串
     * @return 解密后的字符串
     * @throws Exception
     */
    public static String decrypt(String xml) throws Exception {
        return decrypt(xml, strDefaultKey);
    }

    /**
     * 从指定字符串生成密钥，密钥所需的字节数组长度为8位 不足8位时后面补0，超出8位只取前8位
     *
     * @param arrBTmp
     *            构成该字符串的字节数组
     * @return 生成的密钥
     * @throws java.lang.Exception
     */
    private Key getKey(byte[] arrBTmp) throws Exception {
        // 创建一个空的8位字节数组（默认值为0）
        byte[] arrB = new byte[8];

        // 将原始字节数组转换为8位
        for (int i = 0; i < arrBTmp.length && i < arrB.length; i++) {
            arrB[i] = arrBTmp[i];
        }

        // 生成密钥
        Key key = new javax.crypto.spec.SecretKeySpec(arrB, "DES");

        return key;
    }

    /**
     * 获取默认密钥
     * @return
     */
    public static String getDesKey() {
        return DESPlus.strDefaultKey;
    }

    public static void main(String[] args) {
        try {
            //测试密匙
            String key = "BOC_PLFP";
            //004交易案例
            String xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?><ROOT><HEADER><TRANNO>004</TRANNO><BNKNO>17850</BNKNO><COMNO>COM01</COMNO><SN>1109141222222660161</SN></HEADER><BODY><TRANLOG><APPNO>0000000123</APPNO><NOTATION>客户信息不完整，请补充资料。</NOTATION></TRANLOG></BODY></ROOT>";

            System.out.println("密钥：" + key);
            System.out.println("加密前的字符串：" + xml);
            System.out.println("加密前的字符串长度：" + xml.getBytes().length);

            //加密
            xml = DESPlus.encrypt(xml, key);
            System.out.println("加密后的字符串：" + xml);
            System.out.println("加密后的字符串长度：" + xml.getBytes().length);

            //解密
            xml = DESPlus.decrypt(xml, key);
            System.out.println("解密后的字符串：" + xml);
            System.out.println("解密后的字符串长度：" + xml.getBytes().length);

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

上面运行结果为：

密钥：BOC_PLFP
加密前的字符串：<?xml version="1.0" encoding="UTF-8"?><ROOT><HEADER><TRANNO>004</TRANNO><BNKNO>17850</BNKNO><COMNO>COM01</COMNO><SN>1109141222222660161</SN></HEADER><BODY><TRANLOG><APPNO>0000000123</APPNO><NOTATION>客户信息不完整，请补充资料。</NOTATION></TRANLOG></BODY></ROOT>
加密前的字符串长度：262
加密后的字符串：bE5N44gjyfO3SdUs6/OhVg4I4l725S2vWcKBRxYOAd/eAnyuADKXeNNgVXJMj3aJJzndntv364rh
YW2bF33lmEABMU43HfS8DcXX7+QrcIjp3mrk7uJdiNHu4T4oHMeqetFZqU5oh2XY1sbBPPdGEgMf
/OguRVaTblzl/ylkFc6C9BNNSD0IwL0Ks7Mi73+V76P+aFdPgXQc7u4Vkq8Cd6+HgHErbHbJI729
JPJKM5L2YAAW4Q06oi4yMoEASDjYf7Aa1X/FWqclsZImSDB0okGOiuj857l94BM1zYl2RtWdXa9o
0beiL4CbEvKSC3U3PydAI0+mZbtE0sVkyP0sXTke7ifrwiMG
加密后的字符串长度：360
解密后的字符串：<?xml version="1.0" encoding="UTF-8"?><ROOT><HEADER><TRANNO>004</TRANNO><BNKNO>17850</BNKNO><COMNO>COM01</COMNO><SN>1109141222222660161</SN></HEADER><BODY><TRANLOG><APPNO>0000000123</APPNO><NOTATION>客户信息不完整，请补充资料。</NOTATION></TRANLOG></BODY></ROOT>
解密后的字符串长度：262


参考了http://www.lijingquan.net/des-c-php-java.html一文，修改里面的des向量iv，字符编码UTF8为Default等，最终
改写为C#代码如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;

public class DES
{
    private const string defaultKey = "BOC_PLFP"; //默认密钥
    private static byte[] iv = { 0x12, 0x34, 0x56, 0x78, (byte)0x90, (byte)0xab, (byte)0xcd, (byte)0xef };//des 向量
               
    /// <summary>
    ///  des加密
    /// </summary>
    /// <param name="pToEncrypt">要加密的字符串。</param>
    /// <param name="sKey">密钥，且必须为8位。默认公钥加密字符串defaultKey</param>
    /// <returns>以Base64格式返回的加密字符串。</returns>
    public static string Encrypt(string pToEncrypt, string sKey = defaultKey)
    {
        using (DESCryptoServiceProvider des = new DESCryptoServiceProvider())
        {
            byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);
            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
            des.IV = iv;  //ASCIIEncoding.ASCII.GetBytes(sKey);
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            using (CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write))
            {
                cs.Write(inputByteArray, 0, inputByteArray.Length);
                cs.FlushFinalBlock();
                cs.Close();
            }
            string str = Convert.ToBase64String(ms.ToArray());
            ms.Close();
            return str;
        }
    }
            
    /// <summary>
    ///  des解密
    /// </summary>
    /// <param name="pToDecrypt">要解密的以Base64</param>
    /// <param name="sKey">密钥，且必须为8位。默认公钥解密字符串defaultKey</param>
    /// <returns>已解密的字符串。</returns>
    public static string Decrypt(string pToDecrypt, string sKey = defaultKey)
    {
        byte[] inputByteArray = Convert.FromBase64String(pToDecrypt);
        using (DESCryptoServiceProvider des = new DESCryptoServiceProvider())
        {
            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
            des.IV = iv; // ASCIIEncoding.ASCII.GetBytes(sKey);
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            using (CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write))
            {
                cs.Write(inputByteArray, 0, inputByteArray.Length);
                cs.FlushFinalBlock();
                cs.Close();
            }
            string str = Encoding.Default.GetString(ms.ToArray());
            ms.Close();
            return str;
        }
    }
}

经测试，加密和解密的结果和java的一样。