RC4加密算法在C#中的实现
这次的RC4有个基类CryptoBase，这个基类，是为了为多种加密算法提供统一接口而设计的，我这里实现了RC4、DES、RSA三种算法。和C＋＋中一样，C＃这里也要有一个十六进制字符串转换函数来编码解码。
经过测试，客户端C＋＋的RC4能够很好的和服务端C＃中的RC4结合工作，也就是说，一端加密的数据，另一端完全可以解密。很遗憾，实在找不到能和C＃中的RSA算法对应的C＋＋实现的RSA算法，希望得到高人指点……
代码文件有两个：
CryptoBase.cs文件：
以下是代码片段：
using System;
using System.Collections.Generic;
using System.Text;
namespace NewLife.Cryptography
{
/// <summary>
/// 加密类基类
/// </summary>
public class CryptoBase
{
/// <summary>
/// 编码转换器，用于字节码和字符串之间的转换，默认为本机编码
/// </summary>
static public Encoding Encode = Encoding.Default;
public enum EncoderMode { Base64Encoder, HexEncoder };
/// <summary>
/// 带编码模式的字符串加密
/// </summary>
/// <param name="data">要加密的数据</param>
/// <param name="pass">密码</param>
/// <param name="em">编码模式</param>
/// <returns>加密后经过编码的字符串</returns>
public String Encrypt(String data, String pass, CryptoBase.EncoderMode em)
{
if (data == null || pass == null) return null;
if (em == EncoderMode.Base64Encoder)
return Convert.ToBase64String(EncryptEx(Encode.GetBytes(data), pass));
else
return ByteToHex(EncryptEx(Encode.GetBytes(data), pass));
}
/// <summary>
/// 带编码模式的字符串解密
/// </summary>
/// <param name="data">要解密的数据</param>
/// <param name="pass">密码</param>
/// <param name="em">编码模式</param>
/// <returns>明文</returns>
public String Decrypt(String data, String pass, CryptoBase.EncoderMode em)
{
if (data == null || pass == null) return null;
if (em == EncoderMode.Base64Encoder)
return Encode.GetString(DecryptEx(Convert.FromBase64String(data), pass));
else
return Encode.GetString(DecryptEx(HexToByte(data), pass));
}
/// <summary>
/// 加密
/// </summary>
/// <param name="data">要加密的数据</param>
/// <param name="pass">密码</param>
/// <returns>加密后经过默认编码的字符串</returns>
public String Encrypt(String data, String pass)
{
return Encrypt(data, pass, EncoderMode.Base64Encoder);
}
/// <summary>
/// 解密
/// </summary>
/// <param name="data">要解密的经过编码的数据</param>
/// <param name="pass">密码</param>
/// <returns>明文</returns>
public String Decrypt(String data, String pass)
{
return Decrypt(data, pass, EncoderMode.Base64Encoder);
}
/// <summary>
/// 加密
/// </summary>
/// <param name="data">要加密的数据</param>
/// <param name="pass">密钥</param>
/// <returns>密文</returns>
virtual public Byte[] EncryptEx(Byte[] data, String pass) { return null; }
/// <summary>
/// 解密
/// </summary>
/// <param name="data">要解密的数据</param>
/// <param name="pass">密码</param>
/// <returns>明文</returns>
virtual public Byte[] DecryptEx(Byte[] data, String pass) { return null; }
static public Byte[] HexToByte(String szHex)
{
// 两个十六进制代表一个字节
Int32 iLen = szHex.Length;
if (iLen <= 0 || 0 != iLen % 2)
{
return null;
}
Int32 dwCount = iLen / 2;
UInt32 tmp1, tmp2;
Byte[] pbBuffer = new Byte[dwCount];
for (Int32 i = 0; i < dwCount; i++)
{
tmp1 = (UInt32)szHex[i * 2] - (((UInt32)szHex[i * 2] >= (UInt32)'A') ? (UInt32)'A' - 10 : (UInt32)'0');
if (tmp1 >= 16) return null;
tmp2 = (UInt32)szHex[i * 2 + 1] - (((UInt32)szHex[i * 2 + 1] >= (UInt32)'A') ? (UInt32)'A' - 10 : (UInt32)'0');
if (tmp2 >= 16) return null;
pbBuffer[i] = (Byte)(tmp1 * 16 + tmp2);
}
return pbBuffer;
}
static public String ByteToHex(Byte[] vByte)
{
if (vByte == null || vByte.Length < 1) return null;
StringBuilder sb = new StringBuilder(vByte.Length * 2);
for (int i = 0; i < vByte.Length; i++)
{
if ((UInt32)vByte[i] < 0) return null;
UInt32 k = (UInt32)vByte[i] / 16;
sb.Append((Char)(k + ((k > 9) ? 'A' - 10 : '0')));
k = (UInt32)vByte[i] % 16;
sb.Append((Char)(k + ((k > 9) ? 'A' - 10 : '0')));
}
return sb.ToString();
}
}
interface ICrypto
{
/// <summary>
/// 加密
/// </summary>
/// <param name="data">要加密的数据</param>
/// <param name="pass">密钥</param>
/// <returns>密文</returns>
Byte[] EncryptEx(Byte[] data, String pass);
/// <summary>
/// 解密
/// </summary>
/// <param name="data">要解密的数据</param>
/// <param name="pass">密码</param>
/// <returns>明文</returns>
Byte[] DecryptEx(Byte[] data, String pass);
}
}
RC4.cs文件：
以下是代码片段：
using System;
using System.Collections.Generic;
using System.Text;
namespace NewLife.Cryptography
{
public class RC4Crypto : CryptoBase
{
static public RC4Crypto RC4 = new RC4Crypto();
public override Byte[] EncryptEx(Byte[] data, String pass)
{
if (data == null || pass == null) return null;
Byte[] output = new Byte[data.Length];
Int64 i = 0;
Int64 j = 0;
Byte[] mBox = GetKey(Encode.GetBytes(pass), 256);
// 加密
for (Int64 offset = 0; offset < data.Length; offset++)
{
i = (i + 1) % mBox.Length;
j = (j + mBox[i]) % mBox.Length;
Byte temp = mBox[i];
mBox[i] = mBox[j];
mBox[j] = temp;
Byte a = data[offset];
//Byte b = mBox[(mBox[i] + mBox[j] % mBox.Length) % mBox.Length];
// mBox[j] 一定比 mBox.Length 小，不需要在取模
Byte b = mBox[(mBox[i] + mBox[j]) % mBox.Length];
output[offset] = (Byte)((Int32)a ^ (Int32)b);
}
return output;
}
public override Byte[] DecryptEx(Byte[] data, String pass)
{
return EncryptEx(data, pass);
}
/// <summary>
/// 打乱密码
/// </summary>
/// <param name="pass">密码</param>
/// <param name="kLen">密码箱长度</param>
/// <returns>打乱后的密码</returns>
static private Byte[] GetKey(Byte[] pass, Int32 kLen)
{
Byte[] mBox = new Byte[kLen];
for (Int64 i = 0; i < kLen; i++)
{
mBox[i] = (Byte)i;
}
Int64 j = 0;
for (Int64 i = 0; i < kLen; i++)
{
j = (j + mBox[i] + pass[i % pass.Length]) % kLen;
Byte temp = mBox[i];
mBox[i] = mBox[j];
mBox[j] = temp;
}
return mBox;
}
}
}