C#簡單的加密類

public class EncryptHepler {
        // 驗值 
        static string saltValue = "XXXX";
        // 密碼值 
        static string pwdValue = "XXXX";

        /// <summary>
        /// 加密
        /// </summary>
        public static string Encrypt( string input ) {
            byte[ ] data = System.Text.UTF8Encoding.UTF8.GetBytes( input );
            byte[ ] salt = System.Text.UTF8Encoding.UTF8.GetBytes( saltValue );

            // AesManaged - 進階加密標準(AES) 對稱演算法的管理類 
            System.Security.Cryptography.AesManaged aes = new System.Security.Cryptography.AesManaged( );
            // Rfc2898DeriveBytes - 通過使用基於 HMACSHA1 的偽隨機數產生器，實現基於密碼的金鑰衍生函數 (Key Derivation Function) (PBKDF2 - 一種基於密碼的密鑰派生函數) 
            // 通過 密碼 和 salt 衍生金鑰 
            System.Security.Cryptography.Rfc2898DeriveBytes rfc = new System.Security.Cryptography.Rfc2898DeriveBytes( pwdValue, salt );

            aes.BlockSize = aes.LegalBlockSizes[0].MaxSize;
            aes.KeySize = aes.LegalKeySizes[0].MaxSize;
            aes.Key = rfc.GetBytes( aes.KeySize / 8 );
            aes.IV = rfc.GetBytes( aes.BlockSize / 8 );

            // 用當前的 Key 屬性和初始化向量 IV 建立對稱式加密器對象 
            System.Security.Cryptography.ICryptoTransform encryptTransform = aes.CreateEncryptor( );
            // 加密後的輸出資料流 
            System.IO.MemoryStream encryptStream = new System.IO.MemoryStream( );
            // 將加密後的目標流（encryptStream）與加密轉換（encryptTransform）相串連 
            System.Security.Cryptography.CryptoStream encryptor = new System.Security.Cryptography.CryptoStream
                ( encryptStream, encryptTransform, System.Security.Cryptography.CryptoStreamMode.Write );

            // 將一個位元組序列寫入當前 CryptoStream （完成加密的過程）
            encryptor.Write( data, 0, data.Length );
            encryptor.Close( );
            // 將加密後所得到的流轉換成位元組數組，再用Base64編碼將其轉換為字串 
            string encryptedString = Convert.ToBase64String( encryptStream.ToArray( ) );
            return encryptedString;
        }
        /// <summary>
        /// 解密
        /// </summary>
        public static string Decrypt( string input ) {
            byte[ ] encryptBytes = Convert.FromBase64String( input );
            byte[ ] salt = Encoding.UTF8.GetBytes( saltValue );
            System.Security.Cryptography.AesManaged aes = new System.Security.Cryptography.AesManaged( );
            System.Security.Cryptography.Rfc2898DeriveBytes rfc = new System.Security.Cryptography.Rfc2898DeriveBytes( pwdValue, salt );

            aes.BlockSize = aes.LegalBlockSizes[0].MaxSize;
            aes.KeySize = aes.LegalKeySizes[0].MaxSize;
            aes.Key = rfc.GetBytes( aes.KeySize / 8 );
            aes.IV = rfc.GetBytes( aes.BlockSize / 8 );

            // 用當前的 Key 屬性和初始化向量 IV 建立對稱解密器對象 
            System.Security.Cryptography.ICryptoTransform decryptTransform = aes.CreateDecryptor( );
            // 解密後的輸出資料流 
            System.IO.MemoryStream decryptStream = new System.IO.MemoryStream( );

            // 將解密後的目標流（decryptStream）與解密轉換（decryptTransform）相串連 
            System.Security.Cryptography.CryptoStream decryptor = new System.Security.Cryptography.CryptoStream(
                decryptStream, decryptTransform, System.Security.Cryptography.CryptoStreamMode.Write );
            // 將一個位元組序列寫入當前 CryptoStream （完成解密的過程） 
            decryptor.Write( encryptBytes, 0, encryptBytes.Length );
            decryptor.Close( );

            // 將解密後所得到的流轉換為字串 
            byte[ ] decryptBytes = decryptStream.ToArray( );
            string decryptedString = UTF8Encoding.UTF8.GetString( decryptBytes, 0, decryptBytes.Length );
            return decryptedString;
        }
    }//class end