Plan 9 and Inferno at the Google Summer of Code


Today I completed the speaksfor program. This is an Inferno command which will be used to create a SPKI certificate which forms part of a SPKI “speaksfor” chain of delegation of authority. It works like this: the command can be invoked as

   speaksfor S I [T] [V]

where S is the Subject, I is the Issuer, T is an optional tag and V is the optional validity of the certificate. Then a certificate is created which states that Subject S may now speak on behalf of Issuer I regarding the things in the tag T (by default the Subject may speak for I regarding everything). In other words, I delegates part of its authority to S.

In practical terms, currently S is the name of a public key stored in keyfs which I spoke about last time, and I is a public/private key pair read from a file. The Issuer I then signs the certificate with its private key. Although it isn’t essential for my project, I’d like to extend speaksfor so that it can also produce name certificates, which would be used to verify that a user is a member of a group.

As for what I have left to do, there are several things. Right now I’m working on a command that does SPKI reduction. I’ll write about that next time as I only just started this. I also have a couple of minor bugs to fix and man pages to write.