C#实现AES加密解密 - huanglg - 博客园

来源： C#实现AES加密解密 – huanglg – 博客园

AES 高级加密标准（英语：Advanced Encryption Standard，缩写：AES），在密码学中又称Rijndael加密法

Rijndael（读作rain-dahl）是由美国国家标准与技术协会（NIST）所选的高级加密标准（AES）的候选算法。这个标准用来替代原先的DES，已经被多方分析且广为全世界所使用。

Rijndael 算法首先是一个密钥分组加密的算法，通过置换（permutations ）和替换(substitutions）迭代加密，进过多轮操作形成密文。

AES算是Rijndael算法的一种特殊实现，选的分组为128bit（16字节），密钥可以使用128、192 和 256bit三种，而Rijndael使用的密钥和区块长度可以是32位的整数倍，以128位为下限，256比特为上限。加密过程中使用的密钥是由Rijndael密钥生成方案产生。

AES加密过程是在一个4×4的字节矩阵上运作，这个矩阵又称为“状态（state）”，其初值就是一个明文区块（矩阵中一个元素大小就是明文区块中的一个Byte）。（Rijndael加密法因支持更大的区块，其矩阵行数可视情况增加）加密时，各轮AES加密循环（除最后一轮外）均包含4个步骤：
AddRoundKey — 矩阵中的每一个字节都与该次轮秘钥（round key）做XOR运算；每个子密钥由密钥生成方案产生。
SubBytes — 通过非线性的替换函数，用查找表的方式把每个字节替换成对应的字节。
ShiftRows — 将矩阵中的每个横列进行循环式移位。
MixColumns — 为了充分混合矩阵中各个直行的操作。这个步骤使用线性转换来混合每列的四个字节。

RijndaelManager代码实现

1. using System;
2. using System.Collections.Generic;
3. using System.Text;
4. using System.Security.Cryptography;
5. using System.IO;
7. namespace Csharp
8. {
9. class AESHelper
10. {
11. /// <summary>
12. /// AES加密
13. /// </summary>
14. /// <param name=”Data”>被加密的明文</param>
15. /// <param name=”Key”>密钥</param>
16. /// <param name=”Vector”>向量</param>
17. /// <returns>密文</returns>
18. public static String AESEncrypt(String Data, String Key, String Vector)
19. {
20. Byte[] plainBytes = Encoding.UTF8.GetBytes(Data);
22. Byte[] bKey = new Byte[32];
23. Array.Copy(Encoding.UTF8.GetBytes(Key.PadRight(bKey.Length)), bKey, bKey.Length);
24. Byte[] bVector = new Byte[16];
25. Array.Copy(Encoding.UTF8.GetBytes(Vector.PadRight(bVector.Length)), bVector, bVector.Length);
27. Byte[] Cryptograph = null; // 加密后的密文
29. Rijndael Aes = Rijndael.Create();
30. try
31. {
32. // 开辟一块内存流
33. using (MemoryStream Memory = new MemoryStream())
34. {
35. // 把内存流对象包装成加密流对象
36. using (CryptoStream Encryptor = new CryptoStream(Memory,
37. Aes.CreateEncryptor(bKey, bVector),
38. CryptoStreamMode.Write))
39. {
40. // 明文数据写入加密流
41. Encryptor.Write(plainBytes, 0, plainBytes.Length);
42. Encryptor.FlushFinalBlock();
44. Cryptograph = Memory.ToArray();
45. }
46. }
47. }
48. catch
49. {
50. Cryptograph = null;
51. }
53. return Convert.ToBase64String(Cryptograph);
54. }
56. /// <summary>
57. /// AES解密
58. /// </summary>
59. /// <param name=”Data”>被解密的密文</param>
60. /// <param name=”Key”>密钥</param>
61. /// <param name=”Vector”>向量</param>
62. /// <returns>明文</returns>
63. public static String AESDecrypt(String Data, String Key, String Vector)
64. {
65. Byte[] encryptedBytes = Convert.FromBase64String(Data);
66. Byte[] bKey = new Byte[32];
67. Array.Copy(Encoding.UTF8.GetBytes(Key.PadRight(bKey.Length)), bKey, bKey.Length);
68. Byte[] bVector = new Byte[16];
69. Array.Copy(Encoding.UTF8.GetBytes(Vector.PadRight(bVector.Length)), bVector, bVector.Length);
71. Byte[] original = null; // 解密后的明文
73. Rijndael Aes = Rijndael.Create();
74. try
75. {
76. // 开辟一块内存流，存储密文
77. using (MemoryStream Memory = new MemoryStream(encryptedBytes))
78. {
79. // 把内存流对象包装成加密流对象
80. using (CryptoStream Decryptor = new CryptoStream(Memory,
81. Aes.CreateDecryptor(bKey, bVector),
82. CryptoStreamMode.Read))
83. {
84. // 明文存储区
85. using (MemoryStream originalMemory = new MemoryStream())
86. {
87. Byte[] Buffer = new Byte[1024];
88. Int32 readBytes = 0;
89. while ((readBytes = Decryptor.Read(Buffer, 0, Buffer.Length)) > 0)
90. {
91. originalMemory.Write(Buffer, 0, readBytes);
92. }
94. original = originalMemory.ToArray();
95. }
96. }
97. }
98. }
99. catch
100. {
101. original = null;
102. }
103. return Encoding.UTF8.GetString(original);
104. }
108. /// <summary>
109. /// AES加密(无向量)
110. /// </summary>
111. /// <param name=”plainBytes”>被加密的明文</param>
112. /// <param name=”key”>密钥</param>
113. /// <returns>密文</returns>
114. public static string AESEncrypt(String Data, String Key)
115. {
116. MemoryStream mStream = new MemoryStream();
117. RijndaelManaged aes = new RijndaelManaged();
119. byte[] plainBytes = Encoding.UTF8.GetBytes(Data);
120. Byte[] bKey = new Byte[32];
121. Array.Copy(Encoding.UTF8.GetBytes(Key.PadRight(bKey.Length)), bKey, bKey.Length);
123. aes.Mode = CipherMode.ECB;
124. aes.Padding = PaddingMode.PKCS7;
125. aes.KeySize = 128;
126. //aes.Key = _key;
127. aes.Key = bKey;
128. //aes.IV = _iV;
129. CryptoStream cryptoStream = new CryptoStream(mStream, aes.CreateEncryptor(), CryptoStreamMode.Write);
130. try
131. {
132. cryptoStream.Write(plainBytes, 0, plainBytes.Length);
133. cryptoStream.FlushFinalBlock();
134. return Convert.ToBase64String(mStream.ToArray());
135. }
136. finally
137. {
138. cryptoStream.Close();
139. mStream.Close();
140. aes.Clear();
141. }
142. }
145. /// <summary>
146. /// AES解密(无向量)
147. /// </summary>
148. /// <param name=”encryptedBytes”>被加密的明文</param>
149. /// <param name=”key”>密钥</param>
150. /// <returns>明文</returns>
151. public static string AESDecrypt(String Data, String Key)
152. {
153. Byte[] encryptedBytes = Convert.FromBase64String(Data);
154. Byte[] bKey = new Byte[32];
155. Array.Copy(Encoding.UTF8.GetBytes(Key.PadRight(bKey.Length)), bKey, bKey.Length);
157. MemoryStream mStream = new MemoryStream(encryptedBytes);
158. //mStream.Write( encryptedBytes, 0, encryptedBytes.Length );
159. //mStream.Seek( 0, SeekOrigin.Begin );
160. RijndaelManaged aes = new RijndaelManaged();
161. aes.Mode = CipherMode.ECB;
162. aes.Padding = PaddingMode.PKCS7;
163. aes.KeySize = 128;
164. aes.Key = bKey;
165. //aes.IV = _iV;
166. CryptoStream cryptoStream = new CryptoStream(mStream, aes.CreateDecryptor(), CryptoStreamMode.Read);
167. try
168. {
169. byte[] tmp = new byte[encryptedBytes.Length + 32];
170. int len = cryptoStream.Read(tmp, 0, encryptedBytes.Length + 32);
171. byte[] ret = new byte[len];
172. Array.Copy(tmp, 0, ret, 0, len);
173. return Encoding.UTF8.GetString(ret);
174. }
175. finally
176. {
177. cryptoStream.Close();
178. mStream.Close();
179. aes.Clear();
180. }
181. }
182. }
183. }

AesManager代码实现

1. using System;
2. using System.IO;
3. using System.Security.Cryptography;
5. namespace Aes_Example
6. {
7. class AesExample
8. {
9. public static void Main()
10. {
11. try
12. {
13. string original = “Here is some data to encrypt!”;
15. // Create a new instance of the AesManaged
16. // class. This generates a new key and initialization
17. // vector (IV).
18. using (AesManaged myAes = new AesManaged())
19. {
20. // Encrypt the string to an array of bytes.
21. byte[] encrypted = EncryptStringToBytes_Aes(original, myAes.Key, myAes.IV);
23. // Decrypt the bytes to a string.
24. string roundtrip = DecryptStringFromBytes_Aes(encrypted, myAes.Key, myAes.IV);
26. //Display the original data and the decrypted data.
27. Console.WriteLine(“Original: {0}”, original);
28. Console.WriteLine(“Round Trip: {0}”, roundtrip);
29. }
31. }
32. catch (Exception e)
33. {
34. Console.WriteLine(“Error: {0}”, e.Message);
35. }
36. }
37. static byte[] EncryptStringToBytes_Aes(string plainText, byte[] Key, byte[] IV)
38. {
39. // Check arguments.
40. if (plainText == null || plainText.Length <= 0)
41. throw new ArgumentNullException(“plainText”);
42. if (Key == null || Key.Length <= 0)
43. throw new ArgumentNullException(“Key”);
44. if (IV == null || IV.Length <= 0)
45. throw new ArgumentNullException(“IV”);
46. byte[] encrypted;
47. // Create an AesManaged object
48. // with the specified key and IV.
49. using (AesManaged aesAlg = new AesManaged())
50. {
51. aesAlg.Key = Key;
52. aesAlg.IV = IV;
54. // Create a decrytor to perform the stream transform.
55. ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);
57. // Create the streams used for encryption.
58. using (MemoryStream msEncrypt = new MemoryStream())
59. {
60. using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
61. {
62. using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
63. {
65. //Write all data to the stream.
66. swEncrypt.Write(plainText);
67. }
68. encrypted = msEncrypt.ToArray();
69. }
70. }
71. }
74. // Return the encrypted bytes from the memory stream.
75. return encrypted;
77. }
79. static string DecryptStringFromBytes_Aes(byte[] cipherText, byte[] Key, byte[] IV)
80. {
81. // Check arguments.
82. if (cipherText == null || cipherText.Length <= 0)
83. throw new ArgumentNullException(“cipherText”);
84. if (Key == null || Key.Length <= 0)
85. throw new ArgumentNullException(“Key”);
86. if (IV == null || IV.Length <= 0)
87. throw new ArgumentNullException(“IV”);
89. // Declare the string used to hold
90. // the decrypted text.
91. string plaintext = null;
93. // Create an AesManaged object
94. // with the specified key and IV.
95. using (AesManaged aesAlg = new AesManaged())
96. {
97. aesAlg.Key = Key;
98. aesAlg.IV = IV;
100. // Create a decrytor to perform the stream transform.
101. ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);
103. // Create the streams used for decryption.
104. using (MemoryStream msDecrypt = new MemoryStream(cipherText))
105. {
106. using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
107. {
108. using (StreamReader srDecrypt = new StreamReader(csDecrypt))
109. {
111. // Read the decrypted bytes from the decrypting stream
112. // and place them in a string.
113. plaintext = srDecrypt.ReadToEnd();
114. }
115. }
116. }
118. }
120. return plaintext;
121. }
122. }
123. }
124.