要解密的数据的长度无效

[wyman25]

这是一个使用DES进行文件加密的类，只有两个方法，一个是加密方法：public void Encrypt(string FileName)，另一个是解密方法：public void Decrypt(string FileName),能进行加密，但解密时候出现错误，错误信息为：要解密的数据的长度无效。
请高手赐教！
class DESCrypt
{
private string Key = "12345678";
public void Encrypt(string FileName)
{
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
des.Key = ASCIIEncoding.Default.GetBytes(Key);
des.IV = ASCIIEncoding.Default.GetBytes(Key);
FileStream InputFileStream = File.OpenRead(FileName);
byte[] FileStreamArray = new byte[InputFileStream.Length-1];
InputFileStream.Read(FileStreamArray, 0, FileStreamArray.Length);
InputFileStream.Close();
MemoryStream ms = new MemoryStream();
CryptoStream FileCryptoStream = new CryptoStream(ms,des.CreateEncryptor(), CryptoStreamMode.Write);
FileCryptoStream.Write(FileStreamArray, 0, FileStreamArray.Length);
FileCryptoStream.FlushFinalBlock();
InputFileStream = File.OpenWrite(FileName);
foreach (byte b in ms.ToArray())
{
InputFileStream.WriteByte(b);

}
ms.Close();
InputFileStream.Close();
FileCryptoStream.Close();
}
public void Decrypt(string FileName)
{
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
des.Key = ASCIIEncoding.Default.GetBytes(Key);
des.IV = ASCIIEncoding.Default.GetBytes(Key);
FileStream InputFileStream = File.OpenRead(FileName);
byte[] FileStreamArray = new byte[InputFileStream.Length - 1];
InputFileStream.Read(FileStreamArray, 0, FileStreamArray.Length);
InputFileStream.Close();
MemoryStream ms = new MemoryStream();
CryptoStream FileCryptoStream = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
FileCryptoStream.Write(FileStreamArray, 0, FileStreamArray.Length);
FileCryptoStream.FlushFinalBlock();
InputFileStream = File.OpenWrite(FileName);
foreach (byte b in ms.ToArray())
{
InputFileStream.WriteByte(b);

}
ms.Close();
InputFileStream.Close();
FileCryptoStream.Close();
}
}

[周公]

using System;
using System.Security.Cryptography;
using System.Text;
using System.IO;

namespace Common
...{
    /**//// <summary>
    /// DESEncrypt加密解密算法。
    /// </summary>
    public sealed class DESEncrypt
    ...{
        private DESEncrypt()
        ...{
            //
            // TODO: 在此处添加构造函数逻辑
            //
        }

        private static string key = "zhoufoxcn";

        /**//// <summary>
        /// 对称加密解密的密钥
        /// </summary>
        public static string Key
        ...{
            get
            ...{
                return key;
            }
            set
            ...{
                key = value;
            }
        }

        /**//// <summary>
        /// DES加密
        /// </summary>
        /// <param name="encryptString"></param>
        /// <returns></returns>
        public static string DesEncrypt(string encryptString)
        ...{
            byte[] keyBytes = Encoding.UTF8.GetBytes(key.Substring(0, 8));
            byte[] keyIV = keyBytes;
            byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
            DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
            MemoryStream mStream = new MemoryStream();
            CryptoStream cStream = new CryptoStream(mStream, provider.CreateEncryptor(keyBytes, keyIV), CryptoStreamMode.Write);
            cStream.Write(inputByteArray, 0, inputByteArray.Length);
            cStream.FlushFinalBlock();
            return Convert.ToBase64String(mStream.ToArray());
        }

        /**//// <summary>
        /// DES解密
        /// </summary>
        /// <param name="decryptString"></param>
        /// <returns></returns>
        public static string DesDecrypt(string decryptString)
        ...{
            byte[] keyBytes = Encoding.UTF8.GetBytes(key.Substring(0, 8));
            byte[] keyIV = keyBytes;
            byte[] inputByteArray = Convert.FromBase64String(decryptString);
            DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
            MemoryStream mStream = new MemoryStream();
            CryptoStream cStream = new CryptoStream(mStream, provider.CreateDecryptor(keyBytes, keyIV), CryptoStreamMode.Write);
            cStream.Write(inputByteArray, 0, inputByteArray.Length);
            cStream.FlushFinalBlock();
            return Encoding.UTF8.GetString(mStream.ToArray());
        }
    }
}

看看这个，我自己用的，也是我自己写的。

[wyman25]

我手头上这些算法也大把大把的，我不是要算法，是想弄清楚为什么会这样，问题出在哪儿了。
狂顶！

[Luckyboys]

我也在试，首先我发现一个问题就是那个byte[]的数组初始化的时候，我不明白楼主为什么要-1
我把-1去掉了就会正常
但后面会出现一个字符串，而这个字符串在加密后和解密后都是会跟在结尾的（同样的值）

[阿云ivan]

试一下我的方法：

 public string Encrypt(string stringToEncrypt, string sKey)
    {
        DESCryptoServiceProvider des = new DESCryptoServiceProvider();
        byte[] inputByteArray = Encoding.GetEncoding("UTF-8").GetBytes(stringToEncrypt);
        des.Key = ASCIIEncoding.UTF8.GetBytes(sKey);
        des.IV = ASCIIEncoding.UTF8.GetBytes(sKey);
        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();
    }

    public string Decrypt(string stringToDecrypt, string sKey)
    {
        DESCryptoServiceProvider des = new DESCryptoServiceProvider();

        byte[] inputByteArray = new byte[stringToDecrypt.Length / 2];
        for (int x = 0; x < stringToDecrypt.Length / 2; x++)
        {
            int i = (Convert.ToInt32(stringToDecrypt.Substring(x * 2, 2), 16));
            inputByteArray[x] = (byte)i;
        }

        des.Key = ASCIIEncoding.UTF8.GetBytes(sKey);
        des.IV = ASCIIEncoding.UTF8.GetBytes(sKey);
        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());
    }

[wyman25]

啊，真是的，原来就错在-1，原本代码有些地方是复制别人的，加上对数组的创建时候对“下标从0开始”这点上有点模糊，所以就搞错了。大哥谢谢了！

[sxmonsy]

问题解决了?我来接分

[行者无疆-Kevin]

是你加密后的字符串更改过了,你再解密就会出错.
可以调试对比一下

[Luckyboys]

还有就是，你那个解密的File.OpenWrite( FileName );是不能够覆盖完全的

所以顺便把你的类改了一下写入文件和读取密文的地方

class DESCrypt
	{
		private string Key = "12345678";
		public void Encrypt( string FileName )
		{
			DESCryptoServiceProvider des = new DESCryptoServiceProvider();
			des.Key = ASCIIEncoding.Default.GetBytes( Key );
			des.IV = ASCIIEncoding.Default.GetBytes( Key );

			FileStream InputFileStream = File.OpenRead( FileName );
			byte[] FileStreamArray = new byte[InputFileStream.Length];

			InputFileStream.Read( FileStreamArray , 0 , FileStreamArray.Length );
			InputFileStream.Close();

			MemoryStream ms = new MemoryStream();
			CryptoStream FileCryptoStream = new CryptoStream( ms , des.CreateEncryptor() , CryptoStreamMode.Write );
			FileCryptoStream.Write( FileStreamArray , 0 , FileStreamArray.Length );
			FileCryptoStream.Close();

			InputFileStream = File.OpenWrite( FileName );

			foreach( byte b in ms.ToArray() )
			{
				InputFileStream.WriteByte( b );
			}
			ms.Close();
			InputFileStream.Close();
		}

		public void Decrypt( string FileName )
		{
			//生成Provider并设置钥匙
			DESCryptoServiceProvider des = new DESCryptoServiceProvider();
			des.Key = ASCIIEncoding.Default.GetBytes( Key );
			des.IV = ASCIIEncoding.Default.GetBytes( Key );

			//读取已加密数据
			StreamReader reader = new StreamReader( FileName );
			byte[] FileStreamArray = new byte[reader.BaseStream.Length];

			reader.BaseStream.Read( FileStreamArray , 0 , FileStreamArray.Length );
			reader.Close();

			//生成解密流
			MemoryStream ms = new MemoryStream( FileStreamArray );
			CryptoStream FileCryptoStream = new CryptoStream( ms , des.CreateDecryptor() , CryptoStreamMode.Read );
			
			//读取解密了的数据，并写入原来的文件
			BinaryReader br = new BinaryReader( FileCryptoStream );
			FileStreamArray = new byte[1000];

			BinaryWriter bw = new BinaryWriter( new StreamWriter( FileName ).BaseStream );
			int iReadLength;//读取了多长
			while( ( iReadLength = br.Read( FileStreamArray , 0 , 1000 ) ) > 0 )
			{
				bw.Write( FileStreamArray , 0 , iReadLength );
			}

			//关闭
			bw.Close();
			FileCryptoStream.Close();
			ms.Close();
		}
	}

[boois]

4楼的方法是正确的，关键是byte[]和String的无损转换问题

[lihaoran4628513]

结贴了