SPKI-VERIFIER(2) SPKI-VERIFIER(2)
NAME
verifier: verify - verify sequence of SPKI elements
SYNOPSIS
include "bufio.m";
include "sexprs.m";
include "spki.m";
sexprs := load Sexprs Sexprs->PATH;
Sexp: import sexprs;
spki := load SPKI SPKI->PATH;
Name, Seqel, Subject, Valid: import spki;
verifier := load Verifier Verifier->PATH;
Speaksfor: adt {
subject: ref Subject;
name: ref Name;
regarding: ref Sexp;
valid: ref Valid;
};
init: fn();
verify: fn(seq: list of ref Seqel):
(ref Speaksfor, list of ref Seqel, string);
DESCRIPTION
Verifier checks SPKI proof sequences. This initial imple-
mentation provides a single basic operation. Further work
will allow (via channels and processes) verification to
detect and refresh expired credentials, to support `pull'
authentication, for instance.
Init must be called before any other operation of the mod-
ule.
A Speaksfor value represents a claim that a given subject
entity speaks for (on behalf of) a given name regarding a
set of statements, with validity optionally limited to a
given period. That is, when during the agreed time, subject
makes a statement that is in the agreed set, it is treated
as if name had said it directly. The set of statements is
defined by a SPKI `tag' expression, represented as an S-
expression. In particular, the (tag (*)) means that subject
speaks for name about everything. A claim can be taken as
true if supported by acceptable evidence, for instance a
collection of signed certificates.
Verify does the actual verification of a sequence seq of
Page 1 Plan 9 (printed 1/3/25)
SPKI-VERIFIER(2) SPKI-VERIFIER(2)
SPKI certificates, signatures and operations that makes and
supports a claim that an entity speaks for another. It
returns a tuple (claim, badel, err). On success, claim
refers to a Speaksfor value that summaries the statement
verified by the sequence. On failure, claim is nil, badel
is a list of sequence elements headed by the first element
of seq that failed verification, and err is the reason it
failed.
SOURCE
/appl/lib/spki/verifier.b
SEE ALSO
sexprs(2), spki(2)
Page 2 Plan 9 (printed 1/3/25)