Re: [VCARDDAV] Signed vCards

Kevin Marks <> Mon, 01 July 2013 10:32 UTC

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Date: Mon, 01 Jul 2013 03:32:05 -0700
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From: Kevin Marks <>
To: DataPacRat <>
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Cc: Skip Levens <>, Barry Leiba <>, "" <>
Subject: Re: [VCARDDAV] Signed vCards
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do email addresses (or acct: extension thereof per webfinger/fist to
accomodate email-like jabber addresses) and http addresses cover all
practical IDs?
A twitter handle is a URL: @kevinmarks is shorthand for
A facebook ID is an email or a URL - is the
same as

The hCard practice is uid's are URLs

Is there a case I'm missing here?

On Sun, Jun 30, 2013 at 8:13 PM, DataPacRat <> wrote:

> On Sat, Jun 29, 2013 at 9:27 PM, DataPacRat <> wrote:
> > As a related thought; would it be sufficiently useful to add a tag to
> state
> > which of the other fields in that vCard is to be preferred for sorting
> and
> > identification purposes? For example, webfinger and webfist use an email
> > address as the unique identification string; Apple seems to use UID; and
> I'm
> > trying to work with vCards that have little more than a Twitter handle.
> >
> > As a minor variation of the above, perhaps instead of a single canonical
> ID
> > string, a list in preferential order, to allow for better
> interoperability
> > between systems requiring different sorts of ID strings.
> After some initial fiddling around; something at least resembling the
> above seems to be a near-necessity, for the various uses I've been
> able to work with so far.
> The tricky part seems to be that, when taking one authenticated vCard
> and using that identity as an authentication authority itself, there
> isn't any firm rule about what string to use as the identifier for
> that authority. Given that some vCards have email addresses and some
> don't; some have UIDs; some have Twitter handles; etc; there doesn't
> seem to be any practical way to declare that one particular sort of
> field /has/ to be used as a canonical ID-string. So having a
> PREFERRED-ID field to have the option to declare what string is most
> useful to be used as such would make implementing a full-fledged
> authentication system a heckuvalot easier.
> And once the field exists at all, it seems that allowing it to list
> more than one field, presumably in descending order of preference,
> would allow for easier interoperability between vCard systems
> containing different subsets of identifying information. Eg, "The UID
> is the preferred ID-string; but if your particular system doesn't
> handle that, you could use the email address instead, or failing that,
> the nickname."
> As a practical example; the webfist protocol uses email addresses as
> canonical ID strings, which, with a bit of hash function trickery,
> allows for relatively easy lookups in the webfist ID database. Having
> even just a short list of potential ID-strings could allow, if nothing
> else, all of them to be hashed into a similar database, so that in the
> future, someone seeking to authenticate that identity can lookup
> whichever one of those strings they happen to have available to them.
> So unless someone has a better idea, I'm definitely adding this to the
> signed vCard proposal. (And since we seem to have passed the initial
> inquiry stage, I'm updating the subject line accordingly.)
> Thank you for your time,
> --
> DataPacRat
> "Half of knowledge is knowing the questions." -- The Cynic's Book of Wisdom
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