C#之AES加密解密 - 好文

高级加密标准(AES,Advanced Encryption
Standard)为最常见的对称加密算法(微信小程序加密传输就是用这个加密算法的)。对称加密算法也就是加密和解密用相同的密钥，具体的加密流程如下图：（原理：转自https://blog.csdn.net/qq_28205153/article/details/55798628）

代码实例如下：
using System; using System.Text; using System.Security.Cryptography; using
System.IO; namespace Common.Helper.Crypto { /// <summary> /// AES加密解密
/// </summary> public static class AesCrypto {
//对称加密和分组加密中的四种模式(ECB、CBC、CFB、OFB),这三种的区别，主要来自于密钥的长度，16位密钥=128位，24位密钥=192位，32位密钥=256位。
//更多参考：http://www.cnblogs.com/happyhippy/archive/2006/12/23/601353.html
/// <summary> /// 检验密钥是否有效长度【16|24|32】 /// </summary>
/// <param name="key">密钥</param> /// <returns>bool</returns>
private static bool CheckKey(string key) { if
(string.IsNullOrWhiteSpace(key)) return false; if
(16.Equals(key.Length) || 24.Equals(key.Length) || 32.Equals(key.Length))
return true; else return false; }
/// <summary> /// 检验向量是否有效长度【16】 /// </summary>
/// <param name="iv">向量</param> /// <returns>bool</returns>
private static bool CheckIv(string iv) { if
(string.IsNullOrWhiteSpace(iv)) return false; if
(16.Equals(iv.Length)) return true; else
return false; } #region 参数是string类型的 ///
<summary> /// 加密参数：string /// </summary> /// <param
name="palinData">明文</param> /// <param name="key">密钥</param>
/// <param name="iv">向量</param> /// <param
name="encodingType">编码方式</param> /// <returns>string：密文</returns>
public static string Encrypt(string palinData, string key, string iv,
EncodingStrOrByte.EncodingType encodingType =
EncodingStrOrByte.EncodingType.UTF8) { if
(string.IsNullOrWhiteSpace(palinData)) return null; if
(!(CheckKey(key) && CheckIv(iv))) return palinData; byte[]
toEncryptArray = EncodingStrOrByte.GetBytes(palinData, encodingType);
var rm = new RijndaelManaged { IV =
EncodingStrOrByte.GetBytes(iv, encodingType), Key =
EncodingStrOrByte.GetBytes(key, encodingType), Mode =
CipherMode.ECB, Padding = PaddingMode.PKCS7 };
ICryptoTransform cTransform = rm.CreateEncryptor(); byte[]
resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0,
toEncryptArray.Length); return Convert.ToBase64String(resultArray,
0, resultArray.Length); } /// <summary> /// 解密
参数：string /// </summary> /// <param
name="encryptedData">密文</param> /// <param name="key">密钥</param>
/// <param name="iv">向量</param> /// <param
name="encodingType">编码方式</param> /// <returns>string：明文</returns>
public static string Decrypt(string encryptedData, string key, string iv,
EncodingStrOrByte.EncodingType encodingType =
EncodingStrOrByte.EncodingType.UTF8) { if
(string.IsNullOrWhiteSpace(encryptedData)) return null; if
(!(CheckKey(key) && CheckIv(iv))) return encryptedData; byte[]
toEncryptArray = Convert.FromBase64String(encryptedData); var rm =
new RijndaelManaged { IV =
EncodingStrOrByte.GetBytes(iv, encodingType), Key =
EncodingStrOrByte.GetBytes(key, encodingType), Mode =
CipherMode.ECB, Padding = PaddingMode.PKCS7 };
ICryptoTransform cTransform = rm.CreateDecryptor(); byte[]
resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0,
toEncryptArray.Length); return
Encoding.UTF8.GetString(resultArray); } #endregion
#region 参数是byte[]类型的 /// <summary>   /// 加密参数：byte[]
/// </summary>   /// <param name="palinData">明文</param>   ///
<param name="key">密钥</param>   /// <param name="iv">向量</param>
/// <returns>密文</returns>   public static byte[] Encrypt(byte[]
palinData, string key, string iv, EncodingStrOrByte.EncodingType encodingType =
EncodingStrOrByte.EncodingType.UTF8) { if (palinData ==
null) return null; if (!(CheckKey(key) && CheckIv(iv))) return
palinData; byte[] bKey = new byte[32];
Array.Copy(EncodingStrOrByte.GetBytes(key.PadRight(bKey.Length), encodingType),
bKey, bKey.Length); byte[] bVector = new byte[16];
Array.Copy(EncodingStrOrByte.GetBytes(iv.PadRight(bVector.Length),
encodingType), bVector, bVector.Length); byte[] cryptograph = null;
// 加密后的密文   Rijndael Aes = Rijndael.Create(); //
开辟一块内存流   using (MemoryStream Memory = new MemoryStream())
{ // 把内存流对象包装成加密流对象   using (CryptoStream
Encryptor = new CryptoStream(Memory, Aes.CreateEncryptor(bKey, bVector),
CryptoStreamMode.Write)) { // 明文数据写入加密流
Encryptor.Write(palinData, 0, palinData.Length);
Encryptor.FlushFinalBlock(); cryptograph =
Memory.ToArray(); } } return
cryptograph; } /// <summary>   /// 解密参数：byte[]
/// </summary>   /// <param name="encryptedData">被解密的密文</param>
/// <param name="key">密钥</param>   /// <param
name="iv">向量</param>   /// <returns>明文</returns>   public
static byte[] Decrypt(byte[] encryptedData, string key, string iv,
EncodingStrOrByte.EncodingType encodingType =
EncodingStrOrByte.EncodingType.UTF8) { if (encryptedData ==
null) return null; if (!(CheckKey(key) && CheckIv(iv))) return
encryptedData; byte[] bKey = new byte[32];
Array.Copy(EncodingStrOrByte.GetBytes(key.PadRight(bKey.Length), encodingType),
bKey, bKey.Length); byte[] bVector = new byte[16];
Array.Copy(EncodingStrOrByte.GetBytes(iv.PadRight(bVector.Length),
encodingType), bVector, bVector.Length); byte[] original = null; //
解密后的明文   Rijndael Aes = Rijndael.Create(); //
开辟一块内存流，存储密文   using (MemoryStream Memory = new
MemoryStream(encryptedData)) { // 把内存流对象包装成加密流对象
using (CryptoStream Decryptor = new
CryptoStream(Memory,Aes.CreateDecryptor(bKey, bVector),CryptoStreamMode.Read))
{ // 明文存储区   using
(MemoryStream originalMemory = new MemoryStream()) {
byte[] Buffer = new byte[1024]; int
readBytes = 0; while ((readBytes =
Decryptor.Read(Buffer, 0, Buffer.Length)) > 0) {
originalMemory.Write(Buffer, 0, readBytes);
} original = originalMemory.ToArray();
} } } return original;
} #endregion } }

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