Decryption Property
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MachineKeySection.Decryption Property

Specifies the encryption algorithm that is used for encrypting and decrypting forms authentication data.

Namespace:  System.Web.Configuration
Assembly:  System.Web (in System.Web.dll)

<ConfigurationPropertyAttribute("decryption", DefaultValue := "Auto")> _
<TypeConverterAttribute(GetType(WhiteSpaceTrimStringConverter))> _
<StringValidatorAttribute(MinLength := )> _
Public Property Decryption As String

Property Value

Type: System.String
A value that indicates the algorithm that is used to encrypt and decrypt forms authentication data. (For information about how to specify the algorithm that is used when view state is encrypted, see the Validation property.) Auto is the default value.


The selected value is not one of the decryption values.

The Decryption property supports the following decryption values:

  • Auto, which is the default value, specifies that ASP.NET determines which encryption algorithm to use based on configuration default settings.

  • AES, which specifies that ASP.NET uses the AES algorithm to encrypt data. AES is the default algorithm to encrypt data.

  • 3DES, which specifies that ASP.NET uses the TripleDES algorithm to encrypt data.

  • A custom algorithm.

This property is typically set declaratively in the decryption attribute of the machineKey element of the Web.config file. For more information, see the machineKey element.

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

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