C#完全实现AES算法加密解密函数

/// <summary>     /// Aes加密、解密，密钥长度256，密钥长度不大于32个字节     /// </summary>     public class AesCryptoHelper     {         public const string RET_ERROR = "x07x07x07x07x07";         private const string CRYPTO_IV = "XIANJIAN";         private const string CRYPTO_KEY = "XIANJIAN";         private const int CRYPTO_KEY_LENGTH = 32;         private const int CRYPTO_IV_LENGTH = 16;             private AesCryptoServiceProvider m_aesCryptoServiceProvider;         private string m_message;         public string Message         {             get { return m_message; }             set { m_message = value; }         }         private bool m_containKey;         /// <summary>         /// True：密文中包含密钥         /// False：密文中不包含密钥         /// </summary>         public bool ContainKey         {             get { return m_containKey; }             set { m_containKey = value; }         }         public AesCryptoHelper()         {             m_aesCryptoServiceProvider = new AesCryptoServiceProvider();             m_containKey = true;             m_message = string.Empty;         }         public AesCryptoHelper(bool containKey)             : this()         {             m_containKey = containKey;         }         private string Encrypt(string s_crypto, byte[] key, byte[] iv)         {             string s_encryped = string.Empty;             byte[] crypto, encrypted;             ICryptoTransform ct;                 try             {                 crypto = string2Byte(s_crypto);                 m_aesCryptoServiceProvider.Key = key;                 m_aesCryptoServiceProvider.IV = iv;                 ct = m_aesCryptoServiceProvider.CreateEncryptor();                 encrypted = ct.TransformFinalBlock(crypto, 0, crypto.Length);                 if (m_containKey)                 {                     s_encryped += byte2HexString(key);                 }                 s_encryped += byte2HexString(encrypted);                 return s_encryped;             }             catch (Exception ex)             {                 m_message = ex.ToString();                 return RET_ERROR;             }         }         /// <summary>         /// 指定密钥对明文进行AES加密         /// </summary>         /// <param name="s_crypto">明文</param>         /// <param name="s_key">加密密钥</param>         /// <returns></returns>         public string Encrypt(string s_crypto, string s_key)         {             byte[] key = new byte[CRYPTO_KEY_LENGTH], iv = new byte[CRYPTO_IV_LENGTH];                 byte[] temp = string2Byte(s_key);             if (temp.Length > key.Length)             {                 m_message = "Key too long,need less than 32 Bytes key.";                 return RET_ERROR;             }             key = string2Byte(s_key.PadRight(key.Length));             iv = string2Byte(CRYPTO_IV.PadRight(iv.Length));             return Encrypt(s_crypto, key, iv);         }         /// <summary>         /// 动态生成密钥，并对明文进行AES加密         /// </summary>         /// <param name="s_crypto">明文</param>         /// <returns></returns>         public string Encrypt(string s_crypto)         {             byte[] key = new byte[CRYPTO_KEY_LENGTH], iv = new byte[CRYPTO_IV_LENGTH];                 m_aesCryptoServiceProvider.GenerateKey();             key = m_aesCryptoServiceProvider.Key;             iv = string2Byte(CRYPTO_IV.PadRight(iv.Length));             return Encrypt(s_crypto, key, iv);         }             private string Decrypt(string s_encrypted, byte[] key, byte[] iv)         {             string s_decrypted = string.Empty;             byte[] encrypted, decrypted;             ICryptoTransform ct;                 try             {                 encrypted = hexString2Byte(s_encrypted);                 m_aesCryptoServiceProvider.Key = key;                 m_aesCryptoServiceProvider.IV = iv;                 ct = m_aesCryptoServiceProvider.CreateDecryptor();                 decrypted = ct.TransformFinalBlock(encrypted, 0, encrypted.Length);                 s_decrypted += byte2String(decrypted);                 return s_decrypted;             }             catch (Exception ex)             {                 m_message = ex.ToString();                 m_message = "Decrypt fail.";                 return RET_ERROR;             }         }         /// <summary>         /// 从密文中解析出密钥，并对密文进行解密         /// </summary>         /// <param name="s_encrypted">密文</param>         /// <returns></returns>         public string Decrypt(string s_encrypted)         {             string s_key = string.Empty;             byte[] key = new byte[CRYPTO_KEY_LENGTH], iv = new byte[CRYPTO_IV_LENGTH];                 if (s_encrypted.Length <= CRYPTO_KEY_LENGTH * 2)             {                 m_message = "Encrypted string invalid.";                 return RET_ERROR;             }             if (m_containKey)             {                 s_key = s_encrypted.Substring(0, CRYPTO_KEY_LENGTH * 2);                 s_encrypted = s_encrypted.Substring(CRYPTO_KEY_LENGTH * 2);             }             key = hexString2Byte(s_key);             iv = string2Byte(CRYPTO_IV.PadRight(iv.Length));             return Decrypt(s_encrypted, key, iv);         }         /// <summary>         /// 指定密钥，并对密文进行解密         /// </summary>         /// <param name="s_encrypted">密文</param>         /// <param name="s_key">密钥</param>         /// <returns></returns>         public string Decrypt(string s_encrypted, string s_key)         {             byte[] key = new byte[CRYPTO_KEY_LENGTH], iv = new byte[CRYPTO_IV_LENGTH];                 byte[] temp = string2Byte(s_key);             if (temp.Length > key.Length)             {                 m_message = "Key invalid.too long,need less than 32 Bytes";                 return RET_ERROR;             }             key = string2Byte(s_key.PadRight(key.Length));             iv = string2Byte(CRYPTO_IV.PadRight(iv.Length));             if (m_containKey)             {                 s_encrypted = s_encrypted.Substring(CRYPTO_KEY_LENGTH * 2);             }             return Decrypt(s_encrypted, key, iv);         }         private string byte2HexString(byte[] bytes)         {             StringBuilder sb = new StringBuilder();             foreach (byte b in bytes)             {                 sb.AppendFormat("{0:X2}", b);             }             return sb.ToString();         }         private byte[] hexString2Byte(string hex)         {             int len = hex.Length / 2;             byte[] bytes = new byte[len];             for (int i = 0; i < len; i++)             {                 bytes[i] = (byte)(Convert.ToInt32(hex.Substring(i * 2, 2), 16));             }             return bytes;         }         private byte[] string2Byte(string str)         {             return Encoding.UTF8.GetBytes(str);         }         private string byte2String(byte[] bytes)         {             return Encoding.UTF8.GetString(bytes);         }     }