go-macaroon-bakery/macaroon-bakery — pull request #14 by rogpeppe (2014-12-11 10:14:10+00:00)
Title: bakery/checkers: add Declared and InferDeclared

This allows macaroons to declare information by adding a first-party
caveat. The declarations inferred are valid after caveat checking because
we guarantee to check all discharge macaroons when verifying. A client can
add another declaration caveat, but they can't change the value of an existing
declaration.

To come: built in support for third party caveats that require a set of
declarations to be added when discharged.