It calculates a Message Authentication Code (MAC) to verify that data like ViewState or Forms Authentication cookies hasn't been modified by a user or attacker while in transit.
In the landscape of ASP.NET web application development, security is often a complex tapestry of authentication protocols, authorization checks, and encryption standards. Buried deep within the configuration files lies one of the most critical, yet frequently misunderstood, components of the ASP.NET security infrastructure: the <machineKey> element. machinekey validationkey in web.config
<machineKey validationKey="[StrongKeyHere]" ... /> It calculates a Message Authentication Code (MAC) to
The in an ASP.NET web.config file is a cryptographic secret used to ensure the integrity of sensitive data sent between the server and the client. It is part of the configuration section. Core Purpose <machineKey validationKey="[StrongKeyHere]"
<system.web> <machineKey validationKey="..." decryptionKey="..." validation="SHA1" decryption="AES" /> </system.web>
For SHA1 (the older standard), the validationKey should be 128 characters (64 bytes). For HMACSHA256, use 128 characters or more.