What is and what does machineKey do?

Question

I´m seeing methods of encryption, and I´ve seen a lot of this tool: "aspnet_regiis" but I´ve been asked to search about "machineKey" and all I can see is that it is another section of the web.config but don´t know it´s function or what it is per se...

So... I´m asking this simple question: What is and what does machineKey do ?

Regards.

Answer 1

One of the things that the machineKey does is to validate ViewState so that it can't be manipulated by an attacker. Other uses would be similar. If you are running servers behind a load balancer, you need to make your machineKey the same on all servers so that subsequent requests received by another server can perform validation.