change to EXPIRY section of P3P spec

The following is the revised text for the EXPIRY element
section of the P3P spec, as adopted by the Specification
Working Group. Note that we now define a minumum
expiry time of 24 hours and we have clarified the way the expiry
time is calculated.

2.3.2.3.2 The EXPIRY element
----------------------------

The EXPIRY element can be used in a policy reference file and/or in a P3P
policy to state how long the policy reference file (or policy) remains
valid. The expiry is given as either an absolute expiry time, or a relative
expiry time. An absolute expiry time is a time, given in GMT, until which
the policy reference file (or policy) is valid. A relative expiry time
gives a number of seconds for which the policy reference file (or policy)
is valid. This expiry time is relative to the time the policy reference file
(or
policy) was requested or last revalidated by the client. This
computation MUST be done using the time of the original request or
revalidation, and the current time, with both times generated from the
client's clock.  Revalidation is defined in section 13.3 of RFC 2616.

The minimum amount of time for any relative expiration time is 24 hours, or
86400 seconds. Any relative expiration time shorter than 86400 seconds
MUST be treated as being equal to 86400 seconds in a client
implementation.

If a client encounters an absolute expiration time that is in the past, it
MUST act as if NO policy reference file (or policy) is available. See
section 2.4.7 "Absence of Policy Reference File" for the required procedure
in such cases.

Received on Tuesday, 3 April 2001 17:29:13 UTC