构建一个.net的干货类库，以便于快速的开发

　　在开发程序的时候，加密是一个程序一个必须的功能，基本上任何程序都会用到加密，而不同的加密方式又适应不同需求，有些加密是不可逆的，最常见是用于用户密码的加密，因为很多时候程序里面不该显示出用户的明文密码，有些加密是可逆的，大多数用于一些私密的资料，例如用户的联系方式，私密信息等，这种加密方式能很好的保护用户的资料。加密方式有很多种，网上可以查到的加密方式有很多，但是很多都不全面，本文就在这里列出比较全面的加密方式。

　　1、MD5加密

　　这种加密方式不用我介绍了吧，最常见的，是一种不可逆加密

 1  /// <summary>
 2         /// MD5加密（只能转字符串类型）
 3         /// </summary>
 4         /// <param name="str"></param>
 5         /// <returns></returns>
 6         public static string toMD5(string str)
 7         {
 8             string strResult = str;
 9             if (!string.IsNullOrWhiteSpace(str))
10             {
11                 string strSource = str.ToString();
12                 //new  
13                 System.Security.Cryptography.MD5 md5 = new System.Security.Cryptography.MD5CryptoServiceProvider();
14 
15                 //获取密文字节数组  
16                 byte[] bytResult = md5.ComputeHash(System.Text.Encoding.Default.GetBytes(strSource));
17 
18                 //转换成字符串，并取9到25位  
19                 strResult = BitConverter.ToString(bytResult, 4, 8);
20                 //转换成字符串，32位  
21                 //string strResult = BitConverter.ToString(bytResult);  
22 
23                 //BitConverter转换出来的字符串会在每个字符中间产生一个分隔符，需要去除掉  
24                 strResult = strResult.Replace("-", "");
25             }
26             return strResult;
27         }

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　　2、哈希加密

　　（提供参考）

 1 /// <summary>
 2         /// 哈希加密（只能转字符串类型）
 3         /// </summary>
 4         /// <param name="str"></param>
 5         /// <returns></returns>
 6         public static string toHash(string str)
 7         {
 8             string strResult = "";
 9             if (!string.IsNullOrWhiteSpace(str))
10             {
11                 string strSource = str.ToString();
12                 //Create  
13                 System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create();
14 
15                 //注意编码UTF8、UTF7、Unicode等的选择　  
16                 byte[] bytResult = md5.ComputeHash(System.Text.Encoding.UTF8.GetBytes(strSource));
17 
18                 //字节类型的数组转换为字符串  
19                 for (int i = 0; i < bytResult.Length; i++)
20                 {
21                     //16进制转换   
22                     strResult = strResult + bytResult[i].ToString("X");
23                 }
24             }
25             return strResult;
26         }

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　　3、DES加密（解密）

　　这种加密是一种基于密匙的对称加密

 1  #region DES加密
 2         //默认密钥向量
 3         private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
 4         /// <summary>
 5         /// DES加密
 6         /// </summary>
 7         /// <param name="encryptString">待加密的字符串</param>
 8         /// <returns>加密成功返回加密后的字符串，失败返回源串</returns>
 9         public static string toEncryptDES(string encryptString)
10         {
11             try
12             {
13                 string encryptKey = ASCIIEncoding.ASCII.GetString(Keys);
14                 byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));
15                 byte[] rgbIV = Keys;
16                 byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
17                 DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
18                 MemoryStream mStream = new MemoryStream();
19                 CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
20                 cStream.Write(inputByteArray, 0, inputByteArray.Length);
21                 cStream.FlushFinalBlock();
22                 return Convert.ToBase64String(mStream.ToArray());
23             }
24             catch
25             {
26                 return encryptString;
27             }
28         }
29         #endregion
30 
31         #region DES解密
32         /// <summary>
33         /// DES解密
34         /// </summary>
35         /// <param name="decryptString">待解密的字符串</param>
36         /// <returns>解密成功返回解密后的字符串，失败返源串</returns>
37         public static string toDecryptDES(string decryptString)
38         {
39             try
40             {
41                 string decryptKey = ASCIIEncoding.ASCII.GetString(Keys);
42                 byte[] rgbKey = Encoding.UTF8.GetBytes(decryptKey);
43                 byte[] rgbIV = Keys;
44                 byte[] inputByteArray = Convert.FromBase64String(decryptString);
45                 DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();
46                 MemoryStream mStream = new MemoryStream();
47                 CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
48                 cStream.Write(inputByteArray, 0, inputByteArray.Length);
49                 cStream.FlushFinalBlock();
50                 return Encoding.UTF8.GetString(mStream.ToArray());
51             }
52             catch
53             {
54                 return decryptString;
55             }
56         }
57         #endregion

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　　4、RSA加密（解密）

　　RSA是目前最有影响力的公钥加密算法，它能够抵抗到目前为止已知的绝大多数密码攻击。如果有过支付宝开发经验的开发人员对这个一定不陌生。

　　4.1、密匙生成

　　RSA加密方法需要两个文件用来存放公钥和私钥，在程序里建立key文件来存放这两个文件，由于文件是.pem格式的文件目前没有一种好的读取方式，所以先将文件转换成其他格式文件再读取

 1 /// <summary>
 2         /// 密匙生成（慎用）
 3         /// 注意：当使用此方法时会重新生成一次密匙，之前生成的密匙会被覆盖，使用此方法时建议先进行密匙备份
 4         /// 首次使用此方法加密要在程序上建立KeypublicKey.xml和KeyprivateKey.xml两个文件
 5         /// </summary>
 6         public static void CreateKey()
 7         {
 8             using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider())
 9             {
10                 //pem文件解析，把pem转换成xml文件
11                 string fileName = Utiltity.GetRootPath() + @"KeypublicKey.xml";
12                 using (FileStream fsRead = new FileStream(fileName, FileMode.Create))
13                 {
14                     string publicKey = rsa.ToXmlString(false); // 公钥
15                     StreamWriter sw = new StreamWriter(fsRead);
16                     fsRead.SetLength(0);//首先把文件清空了。
17                     sw.Write(publicKey);//写你的字符串。
18                     sw.Close();
19                     string dfileName = System.IO.Path.ChangeExtension(fileName, ".pem");
20                     File.Delete(dfileName);
21                     File.Move(fileName, dfileName);
22                 }
23 
24                 //pem文件解析，把pem转换成xml文件
25                 fileName = Utiltity.GetRootPath() + @"KeyprivateKey.xml";
26                 using (FileStream fsRead = new FileStream(fileName, FileMode.Create))
27                 {
28                     string privateKey = rsa.ToXmlString(true); // 私钥
29                     StreamWriter sw = new StreamWriter(fsRead);
30                     fsRead.SetLength(0);//首先把文件清空了。
31                     sw.Write(privateKey);//写你的字符串。
32                     sw.Close();
33                     string dfileName = System.IO.Path.ChangeExtension(fileName, ".pem");
34                     File.Delete(dfileName);
35                     File.Move(fileName, dfileName);
36                 }
37             }
38         }

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　　4.2加密（解密）

　　解密要基于对称的密匙，如果不是就解密不了

 1 /// <summary>
 2         /// RSA加密
 3         /// </summary>
 4         /// <param name="content">需加密的字符串</param>
 5         /// <returns></returns>
 6         public static string toEncryptRSA(string content)
 7         {
 8             RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
 9             //pem文件解析，把pem转换成xml文件
10             string fileName = Tool.GetRootPath() + @"KeypublicKey.pem";   
11             string dfileName = System.IO.Path.ChangeExtension(fileName, ".xml");   
12             File.Move(fileName, dfileName);
13             //文件读取
14             using (FileStream fsRead = new FileStream(dfileName, FileMode.Open))
15             {
16                 StreamReader sr = new StreamReader(fsRead);
17                 string publickey = sr.ReadLine();//System.Text.Encoding.UTF8.GetString(heByte);
18                 rsa.FromXmlString(publickey);
19                 byte[] cipherbytes = rsa.Encrypt(Encoding.UTF8.GetBytes(content), false);
20                 content = Convert.ToBase64String(cipherbytes); 
21             }
22             File.Move(dfileName, fileName);
23             return content;
24         }
25 
26 /// <summary>
27         /// RSA解密
28         /// </summary>
29         /// <param name="content">加密的字符串</param>
30         /// <returns></returns>
31         public static string toDecryptRSA(string content)
32         {
33             RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
34             //pem文件解析，把pem转换成xml文件
35             string fileName = Tool.GetRootPath() + @"Keyprivatekey.pem";   
36             string dfileName = System.IO.Path.ChangeExtension(fileName, ".xml");   
37             File.Move(fileName, dfileName);
38             //文件读取
39             using (FileStream fsRead = new FileStream(dfileName, FileMode.Open))
40             {
41                 //int fsLen = (int)fsRead.Length;
42                 //byte[] heByte = new byte[fsLen];
43                 StreamReader sr = new StreamReader(fsRead);
44                 string privatekey = sr.ReadLine();//System.Text.Encoding.UTF8.GetString(heByte);
45                 rsa.FromXmlString(privatekey);
46                 byte[] cipherbytes = rsa.Decrypt(Convert.FromBase64String(content), false);
47                 content = Encoding.UTF8.GetString(cipherbytes);
48             }
49             File.Move(dfileName, fileName);
50             return content;
51         }

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　　5、AES对称加密

　　也是一种基于密匙的对称加密

  1  #region AES对称加密
  2         /// <summary>
  3         /// 默认密码钥
  4         /// </summary>
  5         private static string EncryptKey = "6FFDC945FA1752467C7F238A3BAB4FEA";
  6 
  7         /// <summary>
  8         /// 算法初始IV种子
  9         /// </summary>
 10         private static string ivString = "1D2CFACB382AE6AD36BD4F4C";
 11 
 12         /// <summary>
 13         /// AES 加密
 14         /// </summary>
 15         /// <param name="encryptString">待加密密文</param>
 16         /// <param name="key">密钥</param>
 17         /// <returns></returns>
 18         public static string AESEncrypt(string encryptString, string key)
 19         {
 20             if (string.IsNullOrEmpty(encryptString))
 21                 return null;
 22             if (string.IsNullOrEmpty(key)) { throw (new Exception("密钥不得为空")); }
 23             string m_strEncrypt = "";
 24             byte[] m_btIV = Convert.FromBase64String(ivString);
 25             Rijndael m_AESProvider = Rijndael.Create();
 26             try
 27             {
 28                 byte[] m_btEncryptString = Encoding.UTF8.GetBytes(encryptString);
 29                 MemoryStream m_stream = new MemoryStream();
 30                 CryptoStream m_csstream = new CryptoStream(m_stream, m_AESProvider.CreateEncryptor(Encoding.UTF8.GetBytes(key), m_btIV), CryptoStreamMode.Write);
 31                 m_csstream.Write(m_btEncryptString, 0, m_btEncryptString.Length); m_csstream.FlushFinalBlock();
 32                 m_strEncrypt = Convert.ToBase64String(m_stream.ToArray());
 33                 m_strEncrypt = HttpUtility.UrlEncode(m_strEncrypt, Encoding.UTF8);
 34                 m_stream.Close(); m_stream.Dispose();
 35                 m_csstream.Close(); m_csstream.Dispose();
 36             }
 37             catch (IOException ex) { throw ex; }
 38             catch (CryptographicException ex) { throw ex; }
 39             catch (ArgumentException ex) { throw ex; }
 40             catch (Exception ex) { throw ex; }
 41             finally { m_AESProvider.Clear(); }
 42             return m_strEncrypt;
 43         }
 44 
 45         /// <summary>
 46         /// AES 加密
 47         /// </summary>
 48         /// <param name="encryptString">待加密密文</param>
 49         /// <returns></returns>
 50         public static string AESEncrypt(string encryptString)
 51         {
 52             return AESEncrypt(encryptString, EncryptKey);
 53         }
 54         #endregion
 55 
 56         #region AES对称解密
 57         /// <summary>
 58         /// AES 解密
 59         /// </summary>
 60         /// <param name="decryptString">待解密密文</param>
 61         /// <param name="key">解密密钥</param>
 62         /// <returns></returns>
 63         public static string AESDecrypt(string decryptString, string key)
 64         {
 65             if (string.IsNullOrEmpty(decryptString))
 66                 return null;
 67             if (string.IsNullOrEmpty(key)) { throw (new Exception("密钥不得为空")); }
 68             string m_strDecrypt = "";
 69             byte[] m_btIV = Convert.FromBase64String(ivString);
 70             Rijndael m_AESProvider = Rijndael.Create();
 71             try
 72             {
 73                 if (HttpContext.Current == null)
 74                     decryptString = HttpUtility.UrlDecode(decryptString, Encoding.UTF8);
 75                 byte[] m_btDecryptString = Convert.FromBase64String(decryptString);
 76                 MemoryStream m_stream = new MemoryStream();
 77                 CryptoStream m_csstream = new CryptoStream(m_stream, m_AESProvider.CreateDecryptor(Encoding.UTF8.GetBytes(key), m_btIV), CryptoStreamMode.Write);
 78                 m_csstream.Write(m_btDecryptString, 0, m_btDecryptString.Length); m_csstream.FlushFinalBlock();
 79                 m_strDecrypt = Encoding.UTF8.GetString(m_stream.ToArray());
 80                 m_stream.Close(); m_stream.Dispose();
 81                 m_csstream.Close(); m_csstream.Dispose();
 82             }
 83             catch (IOException ex) { throw ex; }
 84             catch (CryptographicException ex) { throw ex; }
 85             catch (ArgumentException ex) { throw ex; }
 86             catch (Exception ex) { throw ex; }
 87             finally { m_AESProvider.Clear(); }
 88             return m_strDecrypt;
 89         }
 90 
 91         /// <summary>
 92         /// AES 解密
 93         /// </summary>
 94         /// <param name="decryptString">待解密密文</param>
 95         /// <returns></returns>
 96         public static string AESDecrypt(string decryptString)
 97         {
 98             return AESDecrypt(decryptString, EncryptKey);
 99         }
100 
101         /// <summary>
102         /// 随机生成密钥
103         /// </summary>
104         /// <returns></returns>
105         public static string GetIv(int n)
106         {
107             char[] arrChar = new char[] { 'a', 'b', 'd', 'c', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'p', 'r', 'q', 's', 't', 'u', 'v', 'w', 'z', 'y', 'x', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'Q', 'P', 'R', 'T', 'S', 'V', 'U', 'W', 'X', 'Y', 'Z' };
108             StringBuilder iv = new StringBuilder();
109             Random rnd = new Random(DateTime.Now.Millisecond);
110             for (int i = 0; i < n; i++)
111             {
112                 iv.Append(arrChar[rnd.Next(0, arrChar.Length)].ToString());
113             }
114             return iv.ToString();
115         }
116         #endregion

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　　本文的加密方式均修改于网络文章，出处已无法一一列举请见谅