Checksums in Links

Stavros Macrakis (
Tue, 25 Jul 95 20:21:03 -0400

In <>,
(Benjamin C. W. Sittler) says:

...should LINKs have an MD (checksum) attribute? That way one could
verify that [an object]... hasn't been replaced without the user

The HTML 3.0 draft has this wherever a reference is possible. See

But I would have thought it would make more sense to include an
(optional) checksum in the UR* itself, rather than requiring every use
of a UR* (within HTML or elsewhere) to have a parallel MD when an MD
is wanted. The URN requirements document explicitly excludes
checksums as part of the URN. The URC effort appears to be, um,

I would appreciate any pointers to a discussion of this trade-off.