AesCryptoServiceProvider Class
Updated: October 2010
Performs symmetric encryption and decryption using the Cryptographic Application Programming Interfaces (CAPI) implementation of the Advanced Encryption Standard (AES) algorithm.
Assembly: System.Core (in System.Core.dll)
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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.
Imports System Imports System.IO Imports System.Security.Cryptography Class AesExample Public Shared Sub Main() Try Dim original As String = "Here is some data to encrypt!" ' Create a new instance of the AesCryptoServiceProvider ' class. This generates a new key and initialization ' vector (IV). Using myAes As New AesCryptoServiceProvider() ' Encrypt the string to an array of bytes. Dim encrypted As Byte() = EncryptStringToBytes_Aes(original, myAes.Key, myAes.IV) ' Decrypt the bytes to a string. Dim roundtrip As String = 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) End Using Catch e As Exception Console.WriteLine("Error: {0}", e.Message) End Try End Sub 'Main Shared Function EncryptStringToBytes_Aes(ByVal plainText As String, ByVal Key() As Byte, ByVal IV() As Byte) As Byte() ' Check arguments. If plainText Is Nothing OrElse plainText.Length <= 0 Then Throw New ArgumentNullException("plainText") End If If Key Is Nothing OrElse Key.Length <= 0 Then Throw New ArgumentNullException("Key") End If If IV Is Nothing OrElse IV.Length <= 0 Then Throw New ArgumentNullException("Key") End If Dim encrypted() As Byte ' Create an AesCryptoServiceProvider object ' with the specified key and IV. Using aesAlg As New AesCryptoServiceProvider() aesAlg.Key = Key aesAlg.IV = IV ' Create a decrytor to perform the stream transform. Dim encryptor As ICryptoTransform = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV) ' Create the streams used for encryption. Dim msEncrypt As New MemoryStream() Using csEncrypt As New CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write) Using swEncrypt As New StreamWriter(csEncrypt) 'Write all data to the stream. swEncrypt.Write(plainText) End Using encrypted = msEncrypt.ToArray() End Using End Using ' Return the encrypted bytes from the memory stream. Return encrypted End Function 'EncryptStringToBytes_Aes Shared Function DecryptStringFromBytes_Aes(ByVal cipherText() As Byte,ByVal Key() As Byte, ByVal IV() As Byte) As String ' Check arguments. If cipherText Is Nothing OrElse cipherText.Length <= 0 Then Throw New ArgumentNullException("cipherText") End If If Key Is Nothing OrElse Key.Length <= 0 Then Throw New ArgumentNullException("Key") End If If IV Is Nothing OrElse IV.Length <= 0 Then Throw New ArgumentNullException("Key") End If ' Declare the string used to hold ' the decrypted text. Dim plaintext As String = Nothing ' Create an AesCryptoServiceProvider object ' with the specified key and IV. Using aesAlg As New AesCryptoServiceProvider() aesAlg.Key = Key aesAlg.IV = IV ' Create a decrytor to perform the stream transform. Dim decryptor As ICryptoTransform = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV) ' Create the streams used for decryption. Using msDecrypt As New MemoryStream(cipherText) Using csDecrypt As New CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read) Using srDecrypt As New StreamReader(csDecrypt) ' Read the decrypted bytes from the decrypting stream ' and place them in a string. plaintext = srDecrypt.ReadToEnd() End Using End Using End Using End Using Return plaintext End Function 'DecryptStringFromBytes_Aes End Class 'AesExample
System.Security.Cryptography.SymmetricAlgorithm
System.Security.Cryptography.Aes
System.Security.Cryptography.AesCryptoServiceProvider
Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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