I have been reading about this Sony vs GeoHot case. I however don't understand what this root key is (I program mainly on windows, linux is blank to me).
@Jeff Parker
The concept is similar to digital signatures. A 'digital signature' is created for an application using this root key, and its validity is checked on the console before execution is allowed. Having the root key allows people to create their own application signatures, thereby allowing 3rd party code to run on the PS3, once a valid signature is generated for it.