In my mind, Kerberos - a system for authenticating users and services on a network is a good solution for you. There is a Perl extension for Kerberos 5 Authen::Krb5 in the CPAN.

Update: It isn't easy solution but, I think, that it's good and power tool for development high-quality software product which needs mechanism of authorization (for example, intranet).

      
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SV* sv_bless(SV* sv, HV* stash);