Re: [URN] Checksums in URNs

Martin J. Duerst (
Fri, 20 Dec 1996 14:13:25 +0100 (MET)

Date: Fri, 20 Dec 1996 14:13:25 +0100 (MET)
From: "Martin J. Duerst" <>
To: Towsner <>
Cc: Larry Masinter <>,,
Subject: Re: [URN] Checksums in URNs
In-Reply-To: <l03010d02aedf9ebe6b3c@[]>
Message-Id: <Pine.SUN.3.95.961220140805.245D-100000@enoshima>

On Thu, 19 Dec 1996, Towsner wrote:

> >Checksums and other kinds of decorations can be done outside the
> >URL. Think of it as a metascheme:
> >          ck:<checksum><url>
> > e.g.     ck:A3Bd:
> =09I like the idea of having the checksum be optional, as a
> meta-scheme.

Same for me.

>I also think the checksum should be limited to alpha-numeric
> characters, to avoid confusion.

What do you mean by "limited to alpha-numeric characters"? Can you be
more precise.

>Perhaps this should be part of the URL
> scheme as well.

If it is a metascheme, then it is a new URI scheme. It doesn't
have to be discussed either in URL nor in URN syntax. It would
go into a separate draft. It has to make sure, on its own,
that it is compatible with the URL/URN syntax.

Perhaps the URL syntax draft, where it speaks about URIs,
could be generalized in the direction of metaschemes.
From=20the syntax viewpoint, we already have two metaschemes
(urn: and ck:), which can even be combined together,
as ck:urn:namespace:NSS.