DES解密出现-“不正确的数据”和“要解密的数据长度无效”-问题，高手来解决！在线等！
源码如下：
/// <summary>
/// 解密给定的字符串
/// </summary>
/// <param name= 'str '> 要解密的字符 </param>
/// <returns> </returns>
public string DecryptString(string str)
{
byte[] ivb=Encoding.ASCII.GetBytes(this.iv);
byte[] keyb=Encoding.ASCII.GetBytes(this.EncryptKey);
byte[] toDecrypt=this.EncodingMode.GetBytes(str);
byte[] deCrypted=new byte[toDecrypt.Length];
ICryptoTransform deCryptor=des.CreateDecryptor(keyb,ivb);
MemoryStream msDecrypt=new MemoryStream(toDecrypt);
CryptoStream csDecrypt=new CryptoStream(msDecrypt,deCryptor,CryptoStreamMode.Read);
try
{
csDecrypt.Read(deCrypted,0,deCrypted.Length);
}
catch(Exception err)
{
throw new ApplicationException(err.Message);
}
finally
{
try
{
msDecrypt.Close();
csDecrypt.Close();
}
catch{;}
}
return this.EncodingMode.GetString(deCrypted);
}
为什么会出现这个问题？

[解决办法]
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Security.Cryptography;
using System.IO;

namespace DES加密解密
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
this.textBox2.Text = DESEncrypt( " " + this.textBox1.Text.ToString().Trim() + " ");
}

//加密
public string DESEncrypt(string pToEncrypt)
{
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
try
{
byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);
//密匙和偏移量
byte[] kkk = new byte[] { 0x16, 0x09, 0x14, 0x15, 0x07, 0x01, 0x05, 0x08 };

byte[] iivv = new byte[] { 0x08, 0x05, 0x01, 0x07, 0x15, 0x14, 0x09, 0x16 };
des.Key = kkk;
des.IV = iivv;

MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
cs.Write(inputByteArray, 0, inputByteArray.Length);
cs.FlushFinalBlock();
StringBuilder ret = new StringBuilder();
foreach (byte b in ms.ToArray())
{
ret.AppendFormat( "{0:X2} ", b);
}
ret.ToString();
return ret.ToString();
}
catch
{
return " ";
}

}

private void button2_Click(object sender, EventArgs e)
{
this.textBox3.Text = DESDecrypt( " " + this.textBox2.Text.ToString().Trim() + " ");
}
//解密
public string DESDecrypt(string pToDecrypt)
{
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
try
{
byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
for (int x = 0; x < pToDecrypt.Length / 2; x++)
{
int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
inputByteArray[x] = (byte)i;
}

byte[] kkk = new byte[] { 0x16, 0x09, 0x14, 0x15, 0x07, 0x01, 0x05, 0x08 };
byte[] iivv = new byte[] { 0x08, 0x05, 0x01, 0x07, 0x15, 0x14, 0x09, 0x16 };
des.Key = kkk;
des.IV = iivv;

MemoryStream ms = new MemoryStream();
CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
cs.Write(inputByteArray, 0, inputByteArray.Length);
cs.FlushFinalBlock();

StringBuilder ret = new StringBuilder();

return System.Text.Encoding.Default.GetString(ms.ToArray());
}
catch
{
return " ";
}
}




}
}