- From: Schleiff, Marty <marty.schleiff@boeing.com>
- Date: Wed, 16 Jul 2008 18:08:29 -0700
- To: "John Bradley" <john.bradley@wingaa.com>, "Erik Hetzner" <erik.hetzner@ucop.edu>
- Cc: "Paul Prescod" <paul@prescod.net>, "Henry S. Thompson" <ht@inf.ed.ac.uk>, "Mark Baker" <distobj@acm.org>, "Booth, David (HP Software - Boston)" <dbooth@hp.com>, <www-tag@w3.org>
- Message-ID: <173625C7A199934BA40AAA1CD296D2B54DE07C@XCH-NW-03P.nw.nos.boeing.com>
Hi John & Erik (& All), I don't like the pattern ARK uses (for reasons already mentioned), and I'm not in favor of using the same pattern for XRI (for the same reasons already mentioned). But I do think it would be interesting to look at expressing ARKs within XRI. I think the problems Erik mentioned align very well with one of the Boeing XRI Use Cases (see <http://wiki.oasis-open.org/xri/BoeingXriUseCases> http://wiki.oasis-open.org/xri/BoeingXriUseCases). Look at the fifth one: "Multiple Identity Providers (for the same entity)". Henry said the metadata for a particular object is intended to be the same no matter which sponsoring organization is asked. Although the Boeing use case describes different metadata being returned by each identity provider, certain metadata items could be intended to carry the same information about a resource no matter which identity provider is asked. An ARK expressed in HXRI that is resolvable now might look like this (unfortunately the delimiter between the NAAN and the name is a slash, which would have to be percent encoded as %2F in an XRI cross reference): http://xri.net/ark.example.org*($ark*12345%2Fabcdefg) <http://xri.net/ark.example.org*($ark*12345%2Fabcdefg> This example assumes that "$ark" gets defined in the XRI "$" dictionary. This is an unambiguous way for the minter to declare (and for the relying party to know) that "12345/abcdefg" is an ARK. It would look a little cleaner if the delimiter between the NAAN and the name were some other character that wouldn't require percent encoding. The power of using XRI for this is that it can work for nearly(?) any type of identifier. Marty.Schleiff@boeing.com; CISSP Associate Technical Fellow - Cyber Identity Specialist Information Security - Technical Controls (206) 679-5933 _____ From: John Bradley [mailto:john.bradley@wingaa.com] Sent: Wednesday, July 16, 2008 5:04 PM To: Erik Hetzner Cc: Paul Prescod; Henry S. Thompson; Mark Baker; Booth, David (HP Software - Boston); www-tag@w3.org Subject: Re: Boeing XRI Use Cases Hi Erik, I think the specific's of ARK are a bit of a diversion from the main topic. If I understood Henrys suggestion correctly he was proposing using a mechanism similar to ARK for indicating to client applications that they are processing an XRI rather than a http: URL. I don't think the proposal went as far as using ARK itself though I could be wrong about that. There seems to be a diversity of opinions regarding the idea of encoding a special identifier at the start of the http: path segment to indicate that a http: URL is something other than a "plain" http: URL. In the ARK case we seem to be encoding a sub scheme in the URL path. So to use the ARK pattern to encode a XRI it would look like: http://xri.example.org/xri:/@boeing*jbradley/+home/+phone Persistent identifiers in XRI would use the ! symbol in the XRI part to indicate persistence, as per the XRI 2.0 spec. I don't personally want to pass any judgement on ARK itself. I think it is a valid pattern for us to consider. It remains to be seen if it is the best of the proposals under consideration. Regards John Bradley OASIS IDTRUST-SC http://xri.net/=jbradley On 16-Jul-08, at 4:40 PM, Erik Hetzner wrote: At Wed, 16 Jul 2008 14:12:43 -0700, "Paul Prescod" <paul@prescod.net> wrote: I don't think that your analogy is quite right. The problem is not that two different URIs address the same resource. The problem is that third-parties are encouraged to make general-purpose software that pulls apart *any* URI and infers something about it on the basis of whether it matches that pattern or not. That software will make the wrong inference if it encounters a legacy URI that just happens to match the pattern. [.] Will this objection hold if third parties do not pull apart any URL, but only the URLs of organizations that have agreed to be part of ARK? In other words, if we know that example.org & example.com have agreed to be a part of ARK, is there a problem with pulling apart http://ark.example.org/ark:/12345/abcdefg and pointing at http://ark.example.com/ark:/12345/abcdefg, knowing that example.org, which no longer exists, was part of the ARK system, and not to pull apart http://ark.example.net/ark:/12345/abcdeg, a site devoted to Arkology? If this does not address the objection, then I am at a loss for a solution to the problem of: | objects that last longer than the organizations that provide | services for them, so when the provider changes it should not affect | the object's identity. [2] that: a) provides HTTP URLs which are resolvable now, b) allows for some simple mechanism to make them resolvable at some point in the future when the sponsoring organization no longer exists, and c) does not have a single point of failure (for instance, PURLs). best, Erik Hetzner (Here of course speaking only for myself, and not for the California Digital Library) 1. http://www.cdlib.org/inside/diglib/ark/ ;; Erik Hetzner, California Digital Library ;; gnupg key id: 1024D/01DB07E3
Received on Thursday, 17 July 2008 01:10:13 UTC