ASP.NET in a Nutshell

Name

<machineKey>

Synopsis

<machineKey
   validationKey="autogenerate|value”
   decryptionKey="autogenerate|value”
   validation="SHA1|MD5|3DES” />

Specifies the settings for cryptographic keys used for validation and decryption of Forms Authentication cookies.

Scope

All

Attributes

validationKey

The key used for validation of forms authentication cookie data, MAC checking of ViewState, and session state cookies. The default is autogenerate, which generates and stores a random key. For web farm implementations, you can set this value to the same 40 to 128-character key value on each server to ensure that all servers can validate successfully.

decryptionKey

The key used for decryption of forms authentication cookie data. The default is autogenerate, which generates and stores a random key. For web farm implementations, you can set this value to the same 40 to 128-character key value on each server to ensure that all servers can validate successfully.

validation

Specifies the type of encryption used for data validation.

Child Elements

None

Notes

For web farms, ensuring that the validationKey and decryptionKey values are synchronized across all servers in the farm is important. If they are not synchronized, you may get errors in Forms Authentication, ViewState errors, or problems with session state.