C# 加密术-阿里云开发者社区

本文是利用一个简单的小例子，简述C#中和加密术有关的内容，仅供学习参考用。

概述

随着信息技术的发展，计算机网络为信息的获取、传输、处理、利用与共享提供了一个高效、快捷、安全的通信环境和传输通道，网络信息安全也变得越来越重要。信息安全主要包括两个方面的内容：信息存储安全和信息传输安全。保证网络中信息安全的主要技术是数据的加密与解密。如下图示，说明了加密与解密的过程。

公式算法表示如下：

加密公式：c=Eke(m) （11.1）解密公式：m=Dkd(c) （11.2）其中m代表明文，c代表密文，E是加密算法，D是解密算法，参数ke称为加密密钥，参数kd称为解密密钥

涉及知识点

HASH算法：散列函数是现代密码系统的基础。这些函数将任意长度的二进制字符串映射为固定长度的二进制字符串（称为散列值）
对称加密算法：指对信息的加密和解密都使用相同的密钥。
非对称加密算法：非对称加密算法对信息的加密与解密使用不同的密钥，用来加密的密钥是可以公开的，用来解密的密钥需要保密
数字签名术：数字签名技术结合散列算法和非对称加密技术来进行篡改检测和解决相关的身份验证问题。这就像在现实生活中用亲笔签名来保证文件或资料的真实性一样。

散列算法

散列算法主要有MD5【Message Digest Algorithm】，RIPEMD160【RACE Integrity Primitives Evaluation Message Digest】和SHA【Secure Hash Algorithm】，SHA又分为SHA1，SHA256，SHA384，SHA512，【散列算法不可逆，是单向操作】如下如所示：

关于散列算法，效果图如下：

HASH算法核心代码如下：

  1 using System;
  2 using System.Collections.Generic;
  3 using System.Linq;
  4 using System.Security.Cryptography;
  5 using System.Text;
  6 using System.Threading.Tasks;
  7 
  8 namespace DemoCrtpto
  9 {
 10     /// <summary>
 11     /// 信息摘要帮助类
 12     /// </summary>
 13     public class HashHelper
 14     {
 15         #region 信息摘要
 16 
 17         /// <summary>
 18         /// MD5信息摘要
 19         /// </summary>
 20         /// <param name="source"></param>
 21         /// <returns></returns>
 22         public static string GetInfoByMd5(string source)
 23         {
 24             HashAlgorithm hash = getHashAlgorithm(HashType.MD5);
 25             return Encrypto(hash, source);
 26         }
 27 
 28         public static string GetInfoBySHA1(string source)
 29         {
 30             HashAlgorithm hash = getHashAlgorithm(HashType.SHA1);
 31             return Encrypto(hash, source);
 32         }
 33 
 34         public static string GetInfoBySHA256(string source)
 35         {
 36             HashAlgorithm hash = getHashAlgorithm(HashType.SHA256);
 37             return Encrypto(hash, source);
 38         }
 39 
 40         public static string GetInfoBySHA384(string source)
 41         {
 42             HashAlgorithm hash = getHashAlgorithm(HashType.SHA384);
 43             return Encrypto(hash, source);
 44         }
 45 
 46         public static string GetInfoBySHA512(string source)
 47         {
 48             HashAlgorithm hash = getHashAlgorithm(HashType.SHA512);
 49             return Encrypto(hash, source);
 50         }
 51 
 52         public static string GetInfoByRipeMD(string source)
 53         {
 54             HashAlgorithm hash = getHashAlgorithm(HashType.RIPEMD);
 55             return Encrypto(hash, source);
 56         }
 57 
 58         #endregion
 59 
 60         /// <summary>
 61         /// 根据类型获取摘要算法名称
 62         /// </summary>
 63         /// <param name="t"></param>
 64         /// <returns></returns>
 65         private static HashAlgorithm getHashAlgorithm(HashType t) {
 66             HashAlgorithm hash;
 67             switch (t) {
 68                 case HashType.MD5:
 69                     hash = new MD5CryptoServiceProvider();
 70                     break;
 71                 case HashType.SHA1:
 72                     hash = new SHA1Managed();
 73                     break;
 74                 case HashType.SHA256:
 75                     hash = new SHA256Managed();
 76                     break;
 77                 case HashType.SHA384:
 78                     hash = new SHA384Managed();
 79                     break;
 80                 case HashType.SHA512:
 81                     hash = new SHA512Managed();
 82                     break;
 83                 case HashType.RIPEMD:
 84                     hash = new RIPEMD160Managed();
 85                     break;
 86                 default:
 87                     hash = new MD5CryptoServiceProvider();
 88                     break;
 89             }
 90             return hash;
 91         }
 92 
 93         /// <summary>
 94         /// 加密
 95         /// </summary>
 96         /// <param name="hash"></param>
 97         /// <param name="source"></param>
 98         /// <returns></returns>
 99         private static string Encrypto(HashAlgorithm hash, string source) {
100             string dest = string.Empty;
101             try
102             {
103                 byte[] btSource = Encoding.Default.GetBytes(source);
104                 byte[] btDest = hash.ComputeHash(btSource);
105                 dest = Convert.ToBase64String(btDest, 0, btDest.Length);
106             }
107             catch (Exception ex)
108             {
109                 throw ex;
110             }
111             return dest;
112         }
113     }
114 
115     /// <summary>
116     /// 信息摘要类型
117     /// </summary>
118     public enum HashType {
119         MD5=0,
120         SHA1=1,
121         SHA256=2,
122         SHA384=3,
123         SHA512=4,
124         RIPEMD=5
125     }
126 }

View Code

对称加密算法

关于对称加密算法，主要有DES【Data Encryption Standard / 数据加密标准】 , 3DES【三重数据加密算法】,RC2【Rivest Cipher】，Rijndael【又称AES:Advanced Encryption Standard】。如下图所示：

关于对称加密算法，效果图如下：

对称加密算法的核心代码如下：

  1 using System;
  2 using System.Collections.Generic;
  3 using System.IO;
  4 using System.Linq;
  5 using System.Security.Cryptography;
  6 using System.Text;
  7 using System.Threading.Tasks;
  8 
  9 namespace DemoCrtpto
 10 {
 11     /// <summary>
 12     /// 对称加密算法帮助类
 13     /// </summary>
 14     public class SymHelper
 15     {
 16         #region DES加密
 17 
 18         /// <summary>
 19         /// DES加密
 20         /// </summary>
 21         /// <param name="source"></param>
 22         /// <param name="key"></param>
 23         /// <param name="iv"></param>
 24         /// <returns></returns>
 25         public static string GetEnCryptoInfoByDES(string source, string key, string iv)
 26         {
 27             SymmetricAlgorithm sym = getSymmetricAlgorithm(SymType.DES);
 28             return Encrypto(sym, source, key, iv);
 29 
 30         }
 31 
 32         /// <summary>
 33         /// DES解密
 34         /// </summary>
 35         /// <param name="dest"></param>
 36         /// <param name="key"></param>
 37         /// <param name="iv"></param>
 38         /// <returns></returns>
 39         public static string GetDeCryptoInfoByDES(string dest, string key, string iv)
 40         {
 41             SymmetricAlgorithm sym = getSymmetricAlgorithm(SymType.DES);
 42             return Decrypto(sym, dest, key, iv);
 43 
 44         }
 45 
 46         #endregion
 47 
 48         #region RC2加密与解密
 49 
 50         /// <summary>
 51         /// RC2加密
 52         /// </summary>
 53         /// <param name="source"></param>
 54         /// <param name="key"></param>
 55         /// <param name="iv"></param>
 56         /// <returns></returns>
 57         public static string GetEnCryptoInfoByRC2(string source, string key, string iv)
 58         {
 59             SymmetricAlgorithm sym = getSymmetricAlgorithm(SymType.RC2);
 60             return Encrypto(sym, source, key, iv);
 61 
 62         }
 63 
 64         /// <summary>
 65         /// RC2解密
 66         /// </summary>
 67         /// <param name="dest"></param>
 68         /// <param name="key"></param>
 69         /// <param name="iv"></param>
 70         /// <returns></returns>
 71         public static string GetDeCryptoInfoByRC2(string dest, string key, string iv)
 72         {
 73             SymmetricAlgorithm sym = getSymmetricAlgorithm(SymType.RC2);
 74             return Decrypto(sym, dest, key, iv);
 75 
 76         }
 77 
 78         #endregion
 79 
 80         #region 3DES加密与解密
 81 
 82         /// <summary>
 83         /// 3DES加密
 84         /// </summary>
 85         /// <param name="source"></param>
 86         /// <param name="key"></param>
 87         /// <param name="iv"></param>
 88         /// <returns></returns>
 89         public static string GetEnCryptoInfoBy3DES(string source, string key, string iv)
 90         {
 91             SymmetricAlgorithm sym = getSymmetricAlgorithm(SymType.TripleDES);
 92             return Encrypto(sym, source, key, iv);
 93 
 94         }
 95 
 96         /// <summary>
 97         /// 3DES解密
 98         /// </summary>
 99         /// <param name="dest"></param>
100         /// <param name="key"></param>
101         /// <param name="iv"></param>
102         /// <returns></returns>
103         public static string GetDeCryptoInfoBy3DES(string dest, string key, string iv)
104         {
105             SymmetricAlgorithm sym = getSymmetricAlgorithm(SymType.TripleDES);
106             return Decrypto(sym, dest, key, iv);
107 
108         }
109 
110         #endregion
111 
112         #region Rijndael加密与解密
113 
114         /// <summary>
115         /// Rijndael加密
116         /// </summary>
117         /// <param name="source"></param>
118         /// <param name="key"></param>
119         /// <param name="iv"></param>
120         /// <returns></returns>
121         public static string GetEnCryptoInfoByRijndael(string source, string key, string iv)
122         {
123             SymmetricAlgorithm sym = getSymmetricAlgorithm(SymType.Rijndael);
124             return Encrypto(sym, source, key, iv);
125 
126         }
127 
128 
129         /// <summary>
130         /// Rijndael解密
131         /// </summary>
132         /// <param name="dest"></param>
133         /// <param name="key"></param>
134         /// <param name="iv"></param>
135         /// <returns></returns>
136         public static string GetDeCryptoInfoByRijndael(string dest, string key, string iv)
137         {
138             SymmetricAlgorithm sym = getSymmetricAlgorithm(SymType.Rijndael);
139             return Decrypto(sym, dest, key, iv);
140         }
141 
142         #endregion
143 
144         public static SymmetricAlgorithm getSymmetricAlgorithm(SymType t)
145         {
146             SymmetricAlgorithm sym;
147             switch (t)
148             {
149                 case SymType.DES:
150                     sym = new DESCryptoServiceProvider();
151                     break;
152                 case SymType.RC2:
153                     sym = new RC2CryptoServiceProvider();
154                     break;
155                 case SymType.TripleDES:
156                     sym = new TripleDESCryptoServiceProvider();
157                     break;
158                 case SymType.Rijndael:
159                     sym = new RijndaelManaged();
160                     break;
161                 default:
162                     sym = new DESCryptoServiceProvider();
163                     break;
164             }
165             return sym;
166         }
167 
168         /// <summary>
169         /// 加密
170         /// </summary>
171         /// <param name="sym"></param>
172         /// <param name="source"></param>
173         /// <param name="key"></param>
174         /// <param name="iv"></param>
175         /// <returns></returns>
176         private static string Encrypto(SymmetricAlgorithm sym, string source, string key, string iv)
177         {
178             string dest = string.Empty;
179             try
180             {
181                 byte[] btnSource = Encoding.Default.GetBytes(source);
182                 //1.创建对称加密算法实例创建对称加密算法实例
183                 sym.Mode = CipherMode.CBC;
184                 int keyLen = sym.LegalKeySizes[0].MaxSize / 8;
185                 int ivLen = sym.BlockSize / 8;
186                 if (key.Length < keyLen)
187                 {
188                     key = key.PadRight(keyLen, '0');
189                 }
190                 if (iv.Length < ivLen)
191                 {
192                     iv = iv.PadRight(ivLen, '0');
193                 }
194                 //使用 PBKDF1 算法的扩展从密码派生密钥
195                 PasswordDeriveBytes pkey = new PasswordDeriveBytes(key,
196     ASCIIEncoding.ASCII.GetBytes("123456"));
197 
198                 //2.设置初始化参数，包括密钥和初始化向量等
199                 sym.Key = pkey.GetBytes(key.Length); //Encoding.Default.GetBytes(key);
200                 sym.IV = Encoding.Default.GetBytes(iv);
201                 //3.使用CreateEncryptor方法创建加密实例
202                 ICryptoTransform trans = sym.CreateEncryptor();
203                 //4.创建加密流
204                 MemoryStream ms = new MemoryStream();
205                 CryptoStream cs = new CryptoStream(ms, trans, CryptoStreamMode.Write);
206                 //5.利用加密流进行数据加密
207                 cs.Write(btnSource, 0, btnSource.Length);
208                 cs.FlushFinalBlock();
209                 //6.返回密文
210                 byte[] cryptoByte = ms.ToArray();
211                 dest = Convert.ToBase64String(cryptoByte, 0, cryptoByte.GetLength(0));
212             }
213             catch (Exception ex)
214             {
215                 throw ex;
216             }
217             return dest;
218         }
219 
220         /// <summary>
221         /// 解密
222         /// </summary>
223         /// <param name="sym"></param>
224         /// <param name="dest"></param>
225         /// <param name="key"></param>
226         /// <param name="iv"></param>
227         /// <returns></returns>
228         private static string Decrypto(SymmetricAlgorithm sym, string dest, string key, string iv)
229         {
230             string source = string.Empty;
231             try
232             {
233                 byte[] btnDest = Convert.FromBase64String(dest);
234                 //1.创建对称加密算法实例创建对称加密算法实例
235                 sym.Mode = CipherMode.CBC;
236                 int keyLen = sym.LegalKeySizes[0].MaxSize / 8;
237                 int ivLen = sym.BlockSize / 8;
238                 if (key.Length < keyLen)
239                 {
240                     key = key.PadRight(keyLen, '0');
241                 }
242                 if (iv.Length < ivLen)
243                 {
244                     iv = iv.PadRight(ivLen, '0');
245                 }
246                 //使用 PBKDF1 算法的扩展从密码派生密钥
247                 PasswordDeriveBytes pkey = new PasswordDeriveBytes(key,
248     ASCIIEncoding.ASCII.GetBytes("123456"));
249                 //2.设置初始化参数，包括密钥和初始化向量等
250                 sym.Key = pkey.GetBytes(key.Length); //Encoding.Default.GetBytes(key);
251                 sym.IV = Encoding.Default.GetBytes(iv);
252                 //3.使用CreateDecryptor方法创建解密实例
253                 ICryptoTransform trans = sym.CreateDecryptor();
254                 //4.创建解密流
255                 MemoryStream ms = new MemoryStream(btnDest, 0, btnDest.Length);
256                 CryptoStream cs = new CryptoStream(ms, trans, CryptoStreamMode.Read);
257 
258                 //5.返回明文
259                 StreamReader sr = new StreamReader(cs);
260                 source = sr.ReadToEnd();
261             }
262             catch (Exception ex)
263             {
264                 throw ex;
265             }
266             return source;
267         }
268     }
269 
270     /// <summary>
271     /// 加密类型
272     /// </summary>
273     public enum SymType {
274         DES=0,
275         RC2=1,
276         TripleDES=2,
277         Rijndael=3
278     }
279 }

View Code

非对称加密算法和数字签名

非对称加密算法，主要要RSA【RSA公钥加密算法是1977年由罗纳德·李维斯特（Ron Rivest）、阿迪·萨莫尔（Adi Shamir）和伦纳德·阿德曼（Leonard Adleman）一起提出的。1987年7月首次在美国公布，当时他们三人都在麻省理工学院工作实习。RSA就是他们三人姓氏开头字母拼在一起组成的。】【非对称加密算法对长度有一定的限制，适用于少量数据】

关于非对称加密算法，效果图如下：

关于数字签名，效果图如下：

关于非对称加密术和数字签名，核心代码如下：

  1 using System;
  2 using System.Collections.Generic;
  3 using System.Linq;
  4 using System.Security.Cryptography;
  5 using System.Text;
  6 using System.Threading.Tasks;
  7 
  8 namespace DemoCrtpto
  9 {
 10     /// <summary>
 11     /// 非对称加密算法帮助类
 12     /// </summary>
 13     public class AsymHelper
 14     {
 15 
 16     }
 17 
 18     public class DSAHelper {
 19 
 20         private static string keyContainerName = "star";
 21 
 22         private static string m_PriKey = string.Empty;
 23 
 24         private static string m_PubKey = string.Empty;
 25 
 26 
 27         public static string PriKey
 28         {
 29             get
 30             {
 31                 return m_PriKey;
 32             }
 33 
 34             set
 35             {
 36                 m_PriKey = value;
 37             }
 38         }
 39 
 40         public static string PubKey
 41         {
 42             get
 43             {
 44                 return m_PubKey;
 45             }
 46 
 47             set
 48             {
 49                 m_PubKey = value;
 50             }
 51         }
 52 
 53         public static void generateKey()
 54         {
 55             CspParameters m_CspParameters;
 56             m_CspParameters = new CspParameters();
 57             m_CspParameters.KeyContainerName = keyContainerName;
 58             DSACryptoServiceProvider asym = new DSACryptoServiceProvider();
 59             m_PriKey = asym.ToXmlString(true);
 60             m_PubKey = asym.ToXmlString(false);
 61             asym.PersistKeyInCsp = false;
 62             asym.Clear();
 63         }
 64 
 65         public static string Encrypto(string source) {
 66             if (string.IsNullOrEmpty(m_PubKey) && string.IsNullOrEmpty(m_PriKey))
 67             {
 68                 generateKey();
 69             }
 70             return getEncryptoInfoByDSA(source);
 71         }
 72 
 73         /// <summary>
 74         /// 创建数字签名
 75         /// </summary>
 76         /// <param name="source"></param>
 77         /// <returns></returns>
 78         public static string getEncryptoInfoByDSA(string source)
 79         {
 80             string dest = string.Empty;
 81             string ss = HashHelper.GetInfoBySHA1(source);
 82             byte[] btSource = Convert.FromBase64String(ss);
 83             DSACryptoServiceProvider asym = new DSACryptoServiceProvider();
 84             asym.FromXmlString(m_PriKey);
 85             DSASignatureFormatter dsaFormatter = new DSASignatureFormatter(asym);
 86             dsaFormatter.SetHashAlgorithm("SHA1");
 87             byte[] btDest = dsaFormatter.CreateSignature(btSource);
 88             dest = Convert.ToBase64String(btDest);
 89             return dest;
 90         }
 91 
 92         /// <summary>
 93         /// 验证数字签名
 94         /// </summary>
 95         /// <param name="source"></param>
 96         /// <param name="dest"></param>
 97         /// <returns></returns>
 98         public static bool verifyInfo(string source, string dest)
 99         {
100             string ss = HashHelper.GetInfoBySHA1(source);
101             byte[] btnSource = Convert.FromBase64String(ss);
102             byte[] btnDest = Convert.FromBase64String(dest);
103             DSACryptoServiceProvider asym = new DSACryptoServiceProvider();
104             asym.FromXmlString(m_PubKey);
105             DSASignatureDeformatter dsaFormatter = new DSASignatureDeformatter(asym);
106             dsaFormatter.SetHashAlgorithm("SHA1");
107             return dsaFormatter.VerifySignature(btnSource, btnDest);
108         }
109     }
110 
111     public class RSAHelper {
112 
113         private static string keyContainerName = "star";
114 
115         private static string m_PriKey = string.Empty;
116 
117         private static string m_PubKey = string.Empty;
118         
119 
120         public static string PriKey
121         {
122             get
123             {
124                 return m_PriKey;
125             }
126 
127             set
128             {
129                 m_PriKey = value;
130             }
131         }
132 
133         public static string PubKey
134         {
135             get
136             {
137                 return m_PubKey;
138             }
139 
140             set
141             {
142                 m_PubKey = value;
143             }
144         }
145 
146         public static string Encrypto(string source) {
147             if (string.IsNullOrEmpty(m_PubKey) && string.IsNullOrEmpty(m_PriKey)) {
148                 generateKey();
149             }
150             return getEncryptoInfoByRSA(source);
151         }
152 
153         public static string Decrypto(string dest) {
154             if (string.IsNullOrEmpty(m_PubKey) && string.IsNullOrEmpty(m_PriKey))
155             {
156                 generateKey();
157             }
158             return getDecryptoInfoByRSA(dest);
159         }
160 
161         public static void generateKey()
162         {
163             CspParameters m_CspParameters;
164             m_CspParameters = new CspParameters();
165             m_CspParameters.KeyContainerName = keyContainerName;
166             RSACryptoServiceProvider asym = new RSACryptoServiceProvider(m_CspParameters);
167 
168             m_PriKey = asym.ToXmlString(true);
169             m_PubKey = asym.ToXmlString(false);
170             asym.PersistKeyInCsp = false;
171             asym.Clear();
172         }
173 
174         public static string getEncryptoInfoByRSA(string source)
175         {
176             byte[] plainByte = Encoding.ASCII.GetBytes(source);
177             //初始化参数
178             RSACryptoServiceProvider asym = new RSACryptoServiceProvider();
179             asym.FromXmlString(m_PubKey);
180             int keySize = asym.KeySize / 8;//非对称加密，每次的长度不能太长，否则会报异常
181             int bufferSize = keySize - 11;
182             if (plainByte.Length > bufferSize) {
183                 throw new Exception("非对称加密最多支持【"+bufferSize+"】字节，实际长度【"+plainByte.Length+"】字节。");
184             }
185             byte[] cryptoByte = asym.Encrypt(plainByte, false);
186             return Convert.ToBase64String(cryptoByte);
187         }
188 
189         public static string getDecryptoInfoByRSA(string dest)
190         {
191             byte[] btDest = Convert.FromBase64String(dest);
192             //初始化参数
193             RSACryptoServiceProvider asym = new RSACryptoServiceProvider();
194             asym.FromXmlString(m_PriKey);
195             int keySize = asym.KeySize / 8;//非对称加密，每次的长度不能太长，否则会报异常
196             //int bufferSize = keySize - 11;
197             if (btDest.Length > keySize)
198             {
199                 throw new Exception("非对称解密最多支持【" + keySize + "】字节，实际长度【" + btDest.Length + "】字节。");
200             }
201             byte[] cryptoByte = asym.Decrypt(btDest, false);
202             return Encoding.ASCII.GetString(cryptoByte);
203         }
204     }
205 
206   
207 
208     public enum AsymType{
209         DSA=0,
210         RSA=1
211     }
212 }