C#帮助类：Base64

  1     public class Base64
  2     {
  3         #region Base64加密
  4         ///<summary>
  5         ///Base64加密
  6         ///</summary>
  7         ///<paramname="Message"></param>
  8         ///<returns></returns>
  9         public static string Base64Code(string Message)
 10         {
 11             char[] Base64Code = new char[] { ‘A‘, ‘B‘, ‘C‘, ‘D‘, ‘E‘, ‘F‘, ‘G‘, ‘H‘, ‘I‘, ‘J‘, ‘K‘, ‘L‘, ‘M‘, ‘N‘, ‘O‘, ‘P‘, ‘Q‘, ‘R‘, ‘S‘, ‘T‘, ‘U‘, ‘V‘, ‘W‘, ‘X‘, ‘Y‘, ‘Z‘, ‘a‘, ‘b‘, ‘c‘, ‘d‘, ‘e‘, ‘f‘, ‘g‘, ‘h‘, ‘i‘, ‘j‘, ‘k‘, ‘l‘, ‘m‘, ‘n‘, ‘o‘, ‘p‘, ‘q‘, ‘r‘, ‘s‘, ‘t‘, ‘u‘, ‘v‘, ‘w‘, ‘x‘, ‘y‘, ‘z‘, ‘0‘, ‘1‘, ‘2‘, ‘3‘, ‘4‘, ‘5‘, ‘6‘, ‘7‘, ‘8‘, ‘9‘, ‘+‘, ‘/‘, ‘=‘ };
 12             byte empty = (byte)0;
 13             System.Collections.ArrayList byteMessage = new System.Collections.ArrayList(System.Text.Encoding.Default.GetBytes(Message));
 14             System.Text.StringBuilder outmessage;
 15             int messageLen = byteMessage.Count;
 16             //将字符分成3个字节一组，如果不足，则以0补齐
 17             int page = messageLen / 3;
 18             int use = 0;
 19             if ((use = messageLen % 3) > 0)
 20             {
 21                 for (int i = 0; i < 3 - use; i++) byteMessage.Add(empty);
 22                 page++;
 23             }
 24             //将3个字节的每组字符转换成4个字节一组的。3个一组，一组一组变成4个字节一组
 25             //方法是：转换成ASCII码，按顺序排列24位数据，再把这24位数据分成4组，即每组6位。再在每组的的最高位前补两个0凑足一个字节。
 26             outmessage = new System.Text.StringBuilder(page * 4); for (int i = 0; i < page; i++)
 27             {
 28                 //取一组3个字节的组
 29                 byte[] instr = new byte[3]; instr[0] = (byte)byteMessage[i * 3]; instr[1] = (byte)byteMessage[i * 3 + 1]; instr[2] = (byte)byteMessage[i * 3 + 2];
 30                 //六个位为一组，补0变成4个字节
 31                 int[] outstr = new int[4];
 32                 //第一个输出字节：取第一输入字节的前6位，并且在高位补0，使其变成8位（一个字节）
 33                 outstr[0] = instr[0] >> 2;
 34                 //第二个输出字节：取第一输入字节的后2位和第二个输入字节的前4位（共6位），并且在高位补0，使其变成8位（一个字节）
 35                 outstr[1] = ((instr[0] & 0x03) << 4) ^ (instr[1] >> 4);
 36                 //第三个输出字节：取第二输入字节的后4位和第三个输入字节的前2位（共6位），并且在高位补0，使其变成8位（一个字节）
 37                 if (!instr[1].Equals(empty)) outstr[2] = ((instr[1] & 0x0f) << 2) ^ (instr[2] >> 6); else outstr[2] = 64;
 38                 //第四个输出字节：取第三输入字节的后6位，并且在高位补0，使其变成8位（一个字节）
 39                 if (!instr[2].Equals(empty)) outstr[3] = (instr[2] & 0x3f); else outstr[3] = 64; outmessage.Append(Base64Code[outstr[0]]);
 40                 outmessage.Append(Base64Code[outstr[1]]);
 41                 outmessage.Append(Base64Code[outstr[2]]);
 42                 outmessage.Append(Base64Code[outstr[3]]);
 43             }
 44             return outmessage.ToString();
 45         }
 46         #endregion Base64加密
 47         #region Base64解密
 48         ///<summary>///Base64解密
 49         ///</summary>
 50         ///<paramname="Message"></param>
 51         ///<returns></returns>
 52         public static string Base64Decode(string Message)
 53         {
 54             if ((Message.Length % 4) != 0)
 55             {
 56                 throw new ArgumentException("不是正确的BASE64编码，请检查。", "Message");
 57             }
 58             if (!System.Text.RegularExpressions.Regex.IsMatch(Message, "^[A-Z0-9/+=]*$", System.Text.RegularExpressions.RegexOptions.IgnoreCase))
 59             {
 60                 throw new ArgumentException("包含不正确的BASE64编码，请检查。", "Message");
 61             }
 62             string Base64Code = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
 63             int page = Message.Length / 4;
 64             System.Collections.ArrayList outMessage = new System.Collections.ArrayList(page * 3);
 65             char[] message = Message.ToCharArray();
 66             for (int i = 0; i < page; i++)
 67             {
 68                 byte[] instr = new byte[4];
 69                 instr[0] = (byte)Base64Code.IndexOf(message[i * 4]);
 70                 instr[1] = (byte)Base64Code.IndexOf(message[i * 4 + 1]);
 71                 instr[2] = (byte)Base64Code.IndexOf(message[i * 4 + 2]);
 72                 instr[3] = (byte)Base64Code.IndexOf(message[i * 4 + 3]);
 73                 byte[] outstr = new byte[3];
 74                 outstr[0] = (byte)((instr[0] << 2) ^ ((instr[1] & 0x30) >> 4));
 75                 if (instr[2] != 64)
 76                 {
 77                     outstr[1] = (byte)((instr[1] << 4) ^ ((instr[2] & 0x3c) >> 2));
 78                 }
 79                 else
 80                 {
 81                     outstr[2] = 0;
 82                 }
 83                 if (instr[3] != 64)
 84                 {
 85                     outstr[2] = (byte)((instr[2] << 6) ^ instr[3]);
 86                 }
 87                 else
 88                 {
 89                     outstr[2] = 0;
 90                 }
 91                 outMessage.Add(outstr[0]);
 92                 if (outstr[1] != 0) outMessage.Add(outstr[1]);
 93                 if (outstr[2] != 0) outMessage.Add(outstr[2]);
 94             }
 95             byte[] outbyte = (byte[])outMessage.ToArray(Type.GetType("System.Byte"));
 96             return System.Text.Encoding.Default.GetString(outbyte);
 97         }
 98         #endregion Base64解密
 99         #region RSA加密解密
100         /// <summary>
101         /// RSA加密
102         /// </summary>
103         /// <param name="publickey"></param>
104         /// <param name="content"></param>
105         /// <returns></returns>
106         public static string RSAEncrypt(string publickey, string content)
107         {
108             publickey = @"<RSAKeyValue><Modulus>5m9m14XH3oqLJ8bNGw9e4rGpXpcktv9MSkHSVFVMjHbfv+SJ5v0ubqQxa5YjLN4vc49z7SVju8s0X4gZ6AzZTn06jzWOgyPRV54Q4I0DCYadWW4Ze3e+BOtwgVU1Og3qHKn8vygoj40J6U85Z/PTJu3hN1m75Zr195ju7g9v4Hk=</Modulus><Exponent>AQAB</Exponent></RSAKeyValue>";
109             RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
110             byte[] cipherbytes;
111             rsa.FromXmlString(publickey);
112             cipherbytes = rsa.Encrypt(Encoding.UTF8.GetBytes(content), false);
113 
114             return Convert.ToBase64String(cipherbytes);
115         }
116 
117         /// <summary>
118         /// RSA解密
119         /// </summary>
120         /// <param name="privatekey"></param>
121         /// <param name="content"></param>
122         /// <returns></returns>
123         public static string RSADecrypt(string privatekey, string content)
124         {
125             privatekey = @"<RSAKeyValue><Modulus>5m9m14XH3oqLJ8bNGw9e4rGpXpcktv9MSkHSVFVMjHbfv+SJ5v0ubqQxa5YjLN4vc49z7SVju8s0X4gZ6AzZTn06jzWOgyPRV54Q4I0DCYadWW4Ze3e+BOtwgVU1Og3qHKn8vygoj40J6U85Z/PTJu3hN1m75Zr195ju7g9v4Hk=</Modulus><Exponent>AQAB</Exponent><P>/hf2dnK7rNfl3lbqghWcpFdu778hUpIEBixCDL5WiBtpkZdpSw90aERmHJYaW2RGvGRi6zSftLh00KHsPcNUMw==</P><Q>6Cn/jOLrPapDTEp1Fkq+uz++1Do0eeX7HYqi9rY29CqShzCeI7LEYOoSwYuAJ3xA/DuCdQENPSoJ9KFbO4Wsow==</Q><DP>ga1rHIJro8e/yhxjrKYo/nqc5ICQGhrpMNlPkD9n3CjZVPOISkWF7FzUHEzDANeJfkZhcZa21z24aG3rKo5Qnw==</DP><DQ>MNGsCB8rYlMsRZ2ek2pyQwO7h/sZT8y5ilO9wu08Dwnot/7UMiOEQfDWstY3w5XQQHnvC9WFyCfP4h4QBissyw==</DQ><InverseQ>EG02S7SADhH1EVT9DD0Z62Y0uY7gIYvxX/uq+IzKSCwB8M2G7Qv9xgZQaQlLpCaeKbux3Y59hHM+KpamGL19Kg==</InverseQ><D>vmaYHEbPAgOJvaEXQl+t8DQKFT1fudEysTy31LTyXjGu6XiltXXHUuZaa2IPyHgBz0Nd7znwsW/S44iql0Fen1kzKioEL3svANui63O3o5xdDeExVM6zOf1wUUh/oldovPweChyoAdMtUzgvCbJk1sYDJf++Nr0FeNW1RB1XG30=</D></RSAKeyValue>";
126             RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
127             byte[] cipherbytes;
128             rsa.FromXmlString(privatekey);
129             cipherbytes = rsa.Decrypt(Convert.FromBase64String(content), false);
130 
131             return Encoding.UTF8.GetString(cipherbytes);
132         }
133         #endregion RSA加密解密
134 
135     }