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AesCryptoServiceProvider Class

Performs symmetric encryption and decryption using the Cryptographic Application Programming Interfaces (CAPI) implementation of the Advanced Encryption Standard (AES) algorithm.

System.Object
  System.Security.Cryptography.SymmetricAlgorithm
    System.Security.Cryptography.Aes
      System.Security.Cryptography.AesCryptoServiceProvider

Namespace:  System.Security.Cryptography
Assembly:  System.Core (in System.Core.dll)

[HostProtectionAttribute(SecurityAction.LinkDemand, MayLeakOnAbort = true)]
public sealed class AesCryptoServiceProvider : Aes

The AesCryptoServiceProvider type exposes the following members.

  NameDescription
Public methodAesCryptoServiceProviderInitializes a new instance of the AesCryptoServiceProvider class.
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  NameDescription
Public propertyBlockSizeGets or sets the block size, in bits, of the cryptographic operation. (Inherited from SymmetricAlgorithm.)
Public propertyFeedbackSizeGets or sets the feedback size, in bits, of the cryptographic operation. (Inherited from SymmetricAlgorithm.)
Public propertyIVGets or sets the initialization vector (IV) for the symmetric algorithm. (Inherited from SymmetricAlgorithm.)
Public propertyKeyGets or sets the symmetric key that is used for encryption and decryption. (Overrides SymmetricAlgorithm.Key.)
Public propertyKeySizeGets or sets the size, in bits, of the secret key. (Overrides SymmetricAlgorithm.KeySize.)
Public propertyLegalBlockSizesGets the block sizes, in bits, that are supported by the symmetric algorithm. (Inherited from SymmetricAlgorithm.)
Public propertyLegalKeySizesGets the key sizes, in bits, that are supported by the symmetric algorithm. (Inherited from SymmetricAlgorithm.)
Public propertyModeGets or sets the mode for operation of the symmetric algorithm. (Inherited from SymmetricAlgorithm.)
Public propertyPaddingGets or sets the padding mode used in the symmetric algorithm. (Inherited from SymmetricAlgorithm.)
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  NameDescription
Public methodClearReleases all resources used by the SymmetricAlgorithm class. (Inherited from SymmetricAlgorithm.)
Public methodCreateDecryptor()Creates a symmetric AES decryptor object using the current key and initialization vector (IV). (Overrides SymmetricAlgorithm.CreateDecryptor().)
Public methodCreateDecryptor(Byte[], Byte[])Creates a symmetric AES decryptor object using the specified key and initialization vector (IV). (Overrides SymmetricAlgorithm.CreateDecryptor(Byte[], Byte[]).)
Public methodCreateEncryptor()Creates a symmetric AES encryptor object using the current key and initialization vector (IV). (Overrides SymmetricAlgorithm.CreateEncryptor().)
Public methodCreateEncryptor(Byte[], Byte[])Creates a symmetric encryptor object using the specified key and initialization vector (IV). (Overrides SymmetricAlgorithm.CreateEncryptor(Byte[], Byte[]).)
Public methodDispose()Releases all resources used by the current instance of the SymmetricAlgorithm class. (Inherited from SymmetricAlgorithm.)
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Public methodGenerateIVGenerates a random initialization vector (IV) to use for the algorithm. (Overrides SymmetricAlgorithm.GenerateIV().)
Public methodGenerateKeyGenerates a random key to use for the algorithm. (Overrides SymmetricAlgorithm.GenerateKey().)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
Public methodValidKeySizeDetermines whether the specified key size is valid for the current algorithm. (Inherited from SymmetricAlgorithm.)
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NoteNote

The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: MayLeakOnAbort. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

The following example demonstrates how to encrypt and decrypt sample data using the AesCryptoServiceProvider class.

using System;
using System.IO;
using System.Security.Cryptography;

namespace Aes_Example
{
    class AesExample
    {
        public static void Main()
        {
            try
            {

                string original = "Here is some data to encrypt!";

                // Create a new instance of the AesCryptoServiceProvider 
                // class.  This generates a new key and initialization  
                // vector (IV). 
                using (AesCryptoServiceProvider myAes = new AesCryptoServiceProvider())
                {

                    // Encrypt the string to an array of bytes. 
                    byte[] encrypted = EncryptStringToBytes_Aes(original, myAes.Key, myAes.IV);

                    // Decrypt the bytes to a string. 
                    string roundtrip = DecryptStringFromBytes_Aes(encrypted, myAes.Key, myAes.IV);

                    //Display the original data and the decrypted data.
                    Console.WriteLine("Original:   {0}", original);
                    Console.WriteLine("Round Trip: {0}", roundtrip);
                }

            }
            catch (Exception e)
            {
                Console.WriteLine("Error: {0}", e.Message);
            }
        }
        static byte[] EncryptStringToBytes_Aes(string plainText, byte[] Key, byte[] IV)
        {
            // Check arguments. 
            if (plainText == null || plainText.Length <= 0)
                throw new ArgumentNullException("plainText");
            if (Key == null || Key.Length <= 0)
                throw new ArgumentNullException("Key");
            if (IV == null || IV.Length <= 0)
                throw new ArgumentNullException("Key");
            byte[] encrypted;
            // Create an AesCryptoServiceProvider object 
            // with the specified key and IV. 
            using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider())
            {
                aesAlg.Key = Key;
                aesAlg.IV = IV;

                // Create a decrytor to perform the stream transform.
                ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);

                // Create the streams used for encryption. 
                using (MemoryStream msEncrypt = new MemoryStream())
                {
                    using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                    {
                        using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
                        {

                            //Write all data to the stream.
                            swEncrypt.Write(plainText);
                        }
                        encrypted = msEncrypt.ToArray();
                    }
                }
            }


            // Return the encrypted bytes from the memory stream. 
            return encrypted;

        }

        static string DecryptStringFromBytes_Aes(byte[] cipherText, byte[] Key, byte[] IV)
        {
            // Check arguments. 
            if (cipherText == null || cipherText.Length <= 0)
                throw new ArgumentNullException("cipherText");
            if (Key == null || Key.Length <= 0)
                throw new ArgumentNullException("Key");
            if (IV == null || IV.Length <= 0)
                throw new ArgumentNullException("IV");

            // Declare the string used to hold 
            // the decrypted text. 
            string plaintext = null;

            // Create an AesCryptoServiceProvider object 
            // with the specified key and IV. 
            using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider())
            {
                aesAlg.Key = Key;
                aesAlg.IV = IV;

                // Create a decrytor to perform the stream transform.
                ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);

                // Create the streams used for decryption. 
                using (MemoryStream msDecrypt = new MemoryStream(cipherText))
                {
                    using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                    {
                        using (StreamReader srDecrypt = new StreamReader(csDecrypt))
                        {

                            // Read the decrypted bytes from the decrypting stream 
                            // and place them in a string.
                            plaintext = srDecrypt.ReadToEnd();
                        }
                    }
                }

            }

            return plaintext;

        }
    }
}

.NET Framework

Supported in: 4.5, 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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