摘要：实现通用的对称加密算法工具类。
在.Net Framework中与安全、加密相关的共有三大类：
- Hash算法：将一个流使用Hash算法计算其相应的Hash值，我们最常见的MD5、SHA1均属于Hash算法。
- 对称算法：顾名思义，可以双向对一个流（Byte数组）进行加密和解密操作，本文主要使用的就是此算法
- 非对称算法：只能单向“加密”一个流（Byte数组），而不能反向解密
在.Net Framework中，涉及对称加密的算法的类有如下一些，其继承结构图为：
其中：SymmetricAlgorithm类为对称算法的根类，其子类为几种对称加密算法，再子类是具体的实现类。
使用对称加密算法实现对称加密时，代码基本类似，我将其封装一下，定义两个类型：
- SymmetricCryptographyTypeEnum枚举：表示系统支持的对称加密类型
- SymmetricCryptographyUtility类：提供对于Byte数组及字符串进行加密及解密的方法
SymmetricCryptographyTypeEnum枚举的定义如下：
1: namespace DHC_Certification_System.CommonLibrary.SymmetricCryptography
2: {3: /// <summary>
4: /// 使用的对称加密类型
5: /// </summary>
6: public enum SymmetricCryptographyTypeEnum
7: { 8: DESCryptoServiceProvider, 9: AesCryptoServiceProvider, 10: RC2CryptoServiceProvider, 11: RijndaelManaged, 12: TripleDESCryptoServiceProvider 13: } 14: }SymmetricCryptographyUtility类定义如下：
1: using System;
2: using System.IO;
3: using System.Security.Cryptography;
4: using System.Text;
5: 6: namespace DHC_Certification_System.CommonLibrary.SymmetricCryptography
7: {8: /// <summary>
9: /// 对称加密工具类
10: /// </summary>
11: public sealed class SymmetricCryptographyUtility
12: {13: /// <summary>
14: /// 对称加密类的驱动类型
15: /// </summary>
16: private readonly SymmetricAlgorithm _Provider;
17: 18: /// <summary>
19: /// 构造方法，使用自定义的的IV和KEY
20: /// </summary>
21: /// <param name="cryptType">使用的加密算法</param>
22: /// <param name="iv">IV值</param>
23: /// <param name="key">KEY值</param>
24: public SymmetricCryptographyUtility(
25: SymmetricCryptographyTypeEnum cryptType,26: byte[] iv, byte[] key)
27: {28: switch (cryptType)
29: {30: case SymmetricCryptographyTypeEnum.DESCryptoServiceProvider:
31: _Provider = new DESCryptoServiceProvider();
32: break;
33: case SymmetricCryptographyTypeEnum.AesCryptoServiceProvider:
34: _Provider = new AesCryptoServiceProvider();
35: break;
36: case SymmetricCryptographyTypeEnum.RC2CryptoServiceProvider:
37: _Provider = new RC2CryptoServiceProvider();
38: break;
39: case SymmetricCryptographyTypeEnum.RijndaelManaged:
40: _Provider = new RijndaelManaged();
41: break;
42: case SymmetricCryptographyTypeEnum.TripleDESCryptoServiceProvider:
43: _Provider = new TripleDESCryptoServiceProvider();
44: break;
45: } 46: 47: _Provider.IV = iv; 48: _Provider.Key = key; 49: } 50: 51: public SymmetricAlgorithm Provider
52: { 53: get 54: {55: return _Provider;
56: } 57: } 58: 59: /// <summary>
60: /// 加密字符串
61: /// </summary>
62: /// <param name="input"></param>
63: /// <returns></returns>
64: public string EncryptBase64String(string input)
65: {66: string result = null;
67: 68: if (string.IsNullOrEmpty(input) == false)
69: {70: byte[] inputArray = Encoding.Unicode.GetBytes(input);
71: byte[] cryptArray = EncryptByteArray(inputArray);
72: 73: result = Convert.ToBase64String(cryptArray); 74: } 75: 76: return result;
77: } 78: 79: /// <summary>
80: /// 解密字符串
81: /// </summary>
82: /// <param name="input"></param>
83: /// <returns></returns>
84: public string DecryptBase64String(string input)
85: {86: string result = null;
87: 88: if (string.IsNullOrEmpty(input) == false)
89: {90: byte[] inputArray = Convert.FromBase64String(input);
91: byte[] cryptArray = DecryptByteArray(inputArray);
92: 93: result = Encoding.Unicode.GetString(cryptArray); 94: } 95: 96: return result;
97: } 98: 99: /// <summary>
100: /// 加密Byte数组
101: /// </summary>
102: /// <param name="input"></param>
103: /// <returns></returns>
104: public byte[] EncryptByteArray(byte[] input)
105: {106: MemoryStream ms = new MemoryStream();
107: 108: CryptoStream cs = new CryptoStream(
109: ms, _Provider.CreateEncryptor(), CryptoStreamMode.Write); 110: 111: cs.Write(input, 0, input.Length); 112: cs.FlushFinalBlock(); 113: 114: byte[] result = ms.ToArray();
115: 116: cs.Close(); 117: ms.Close(); 118: 119: return result;
120: } 121: 122: /// <summary>
123: /// 解密Byte数组
124: /// </summary>
125: /// <param name="input"></param>
126: /// <returns></returns>
127: public byte[] DecryptByteArray(byte[] input)
128: {129: MemoryStream ms = new MemoryStream();
130: 131: CryptoStream cs = new CryptoStream(
132: ms, _Provider.CreateDecryptor(), CryptoStreamMode.Write); 133: 134: cs.Write(input, 0, input.Length); 135: cs.FlushFinalBlock(); 136: 137: byte[] result = ms.ToArray();
138: 139: cs.Close(); 140: ms.Close(); 141: 142: return result;
143: } 144: } 145: }此类的类成员为：
- 构造方法有三个参数：一个为使用的对称加密算法的类型，后两个是对称加密算法对应的IV及KEY值（需要注意的是，不同的算法要求的IV和KEY使用的Byte数组的长度不同，具体可查阅MSDN）
- EncryptByteArray和DecryptByteArray两个方法是针对于Byte数组的加密与解密
- EncryptBase64String和DecryptBase64String两个方法是针对于字符串的加密与解密
定义如下的单体测试代码：
1: using System;
2: using System.Text;
3: using CommonUtilityLibrary.SymmetricCryptography;
4: using Microsoft.VisualStudio.TestTools.UnitTesting;
5: 6: namespace ExamSolution.SolutionUnitTestProject.CommonUtilityLibrary.SymmetricCryptography
7: {8: /// <summary>
9: /// 对称加密算法加密、解密测试
10: /// </summary>
11: [TestClass]12: public class SymmetricCryptUnitTest
13: {14: #region 各种Provider的对称加字算法的默认IV和KEY
15: private const string IV_DESCRYPTOSERVICEPROVIDER = @"/KiP+1c5dZA=";
16: private const string KEY_DESCRYPTOSERVICEPROVIDER = @"AuNOICVT27g=";
17: 18: private const string IV_AESCRYPTOSERVICEPROVIDER = @"xMHcVFe6M0cFuj2XwDxW4g==";
19: private const string KEY_AESCRYPTOSERVICEPROVIDER = @"2lrJwsLB3yejIqaxp5AHo+KFIzQnHbMG6bJB70L4bfo=";
20: 21: private const string IV_RC2CRYPTOSERVICEPROVIDER = @"SfcSRMSyCD4=";
22: private const string KEY_RC2CRYPTOSERVICEPROVIDER = @"IN4Gg2FNrlEl82VRUBewaA==";
23: 24: private const string IV_RIJNDAELMANAGED = @"bv28soM12cTLKd1ObZV5RA==";
25: private const string KEY_RIJNDAELMANAGED = @"u7R7DbMcCrh9MynjARrEsr0wIUFy9GujyHddE2k7Ric=";
26: 27: private const string IV_TRIPLEDESCRYPTOSERVICEPROVIDER = @"cd8FQK7xXDk=";
28: private const string KEY_TRIPLEDESCRYPTOSERVICEPROVIDER = @"RpbofS6+6f1cE6HzpoAhmZ8kM0PXvNS/";
29: #endregion
30: 31: /// <summary>
32: /// 测试方法
33: /// </summary>
34: [TestMethod]35: public void SymmetricCryptographyUtility()
36: {37: Console.WriteLine("测试开始：");
38: 39: string baseString = "Hello World";
40: byte[] baseByte = new byte[] {0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef};
41: 42: Console.WriteLine("原始字符串为：{0}",baseString);
43: Console.WriteLine("原始Byte数组为：{0}", ConvertByteToHexString(baseByte));
44: 45: SymmetricCryptographyUtility[] crypts = new SymmetricCryptographyUtility[5];
46: 47: crypts[0] = new SymmetricCryptographyUtility(
48: SymmetricCryptographyTypeEnum.DESCryptoServiceProvider, 49: Convert.FromBase64String(IV_DESCRYPTOSERVICEPROVIDER), 50: Convert.FromBase64String(KEY_DESCRYPTOSERVICEPROVIDER));51: crypts[1] = new SymmetricCryptographyUtility(
52: SymmetricCryptographyTypeEnum.AesCryptoServiceProvider, 53: Convert.FromBase64String(IV_AESCRYPTOSERVICEPROVIDER), 54: Convert.FromBase64String(KEY_AESCRYPTOSERVICEPROVIDER));55: crypts[2] = new SymmetricCryptographyUtility(
56: SymmetricCryptographyTypeEnum.RC2CryptoServiceProvider, 57: Convert.FromBase64String(IV_RC2CRYPTOSERVICEPROVIDER), 58: Convert.FromBase64String(KEY_RC2CRYPTOSERVICEPROVIDER));59: crypts[3] = new SymmetricCryptographyUtility(
60: SymmetricCryptographyTypeEnum.RijndaelManaged, 61: Convert.FromBase64String(IV_RIJNDAELMANAGED), 62: Convert.FromBase64String(KEY_RIJNDAELMANAGED));63: crypts[4] = new SymmetricCryptographyUtility(
64: SymmetricCryptographyTypeEnum.TripleDESCryptoServiceProvider, 65: Convert.FromBase64String(IV_TRIPLEDESCRYPTOSERVICEPROVIDER), 66: Convert.FromBase64String(KEY_TRIPLEDESCRYPTOSERVICEPROVIDER)); 67: 68: foreach (SymmetricCryptographyUtility crypt in crypts)
69: {70: Console.WriteLine("====================================================");
71: Console.WriteLine("加密算法的类型为：{0}", crypt.Provider.GetType().Name);
72: 73: string cryptString = crypt.EncryptBase64String(baseString);
74: string deCryptString = crypt.DecryptBase64String(cryptString);
75: Console.WriteLine("加密后的字符串为：{0}",cryptString);
76: Console.WriteLine("解密后的字符串为：{0}", deCryptString);
77: 78: byte[] cryptByte = crypt.EncryptByteArray(baseByte);
79: byte[] deCryptByte = crypt.DecryptByteArray(cryptByte);
80: Console.WriteLine("加密后的Byte数组为：{0}", ConvertByteToHexString(cryptByte));
81: Console.WriteLine("解密后的Byte数组为：{0}", ConvertByteToHexString(deCryptByte));
82: } 83: } 84: 85: /// <summary>
86: /// 将Byte数组转换为字符串，其中每个Byte转换为两位十六进制的数字表示的字符串
87: /// </summary>
88: /// <param name="items"></param>
89: /// <returns></returns>
90: private string ConvertByteToHexString(byte[] items)
91: {92: StringBuilder builder = new StringBuilder();
93: foreach (byte item in items)
94: {95: builder.Append(item.ToString("X2"));
96: }97: return builder.ToString();
98: } 99: } 100: }测试结果如下：
本文源代码下载
http://files.cnblogs.com/DragonInSea/ExamSolution_03.rar
《企业考试系统》项目实践索引页：
http://www.cnblogs.com/DragonInSea/archive/2010/06/02/1749762.html
