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MachineKeySection.ValidationKey Property

Gets or sets the key that is used to validate forms authentication and view state data, or the process by which the key is generated.

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

<StringValidatorAttribute(MinLength := )> _
<ConfigurationPropertyAttribute("validationKey", DefaultValue := "AutoGenerate,IsolateApps")> _
<TypeConverterAttribute(GetType(WhiteSpaceTrimStringConverter))> _
Public Property ValidationKey As String

Property Value

Type: System.String
A key value, or a value that indicates how the key is generated. The default is "AutoGenerate,IsolateApps".

The ValidationKey property is used when enableViewStateMAC is true to create a message authentication code (MAC) to enable ASP.NET to determine whether view state has been tampered with. The ValidationKey property is also used to generate out-of-process, application-specific session IDs to ensure that session state variables are isolated between applications.

Use the "AutoGenerate" option to specify that ASP.NET generates a random key and stores it in the Local Security Authority. The "AutoGenerate" option is part of the default value.

If you add the "IsolateApps" modifier to the "AutoGenerate" ValidationKey value, ASP.NET generates a unique encrypted key for each application by using each application's application ID. "IsolateApps" is also part of the default value.

If you need to support configuration across a network of Web servers (a Web farm), set the ValidationKey property manually to ensure consistent configuration. For information about how to manually generate values for the DecryptionKey attribute, see How To: Configure MachineKey in ASP.NET 2.0.

This property is typically set declaratively in the validationKey attribute of the machineKey element of the Web.config file.

The following example shows how to set the ValidationKey property by using code. This example is part of a larger example provided for the MachineKeySection class.

' Display ValidationKey property.
Console.WriteLine("ValidationKey: {0}", _

.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.