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Re: Today's presentation on Credentials v Capabilities

From: Daniel Hardman <daniel.hardman@evernym.com>
Date: Tue, 18 Feb 2020 11:52:30 -0700
Message-ID: <CAFBYrUp_2JNwu7d_jqu5drvj-vRUrgg+c7M=kHGzTZMs0dVYRg@mail.gmail.com>
To: Joe Andrieu <joe@legreq.com>
Cc: Credentials Community Group <public-credentials@w3.org>
FWIW, I would like to offer the following alternative perspective to the
ideas in Joe's slides.

1. Credentials can be made delegatable, and they can be attenuated. This
collapses the most interesting differences between credentials and
capabilities, making a special new data format for capabilities
unnecessary. Capabilities can be done with VCs (any type that's

2. The problem of extending privileges (delegation and attenuation) is
actually a special case of the more general problem of data provenance.
Delegation just requires that we show the provenance of privileges (did
these privileges derive from someone who had them to give away?). But
solving the data provenance problem has additional far-reaching benefits (a
small employer can prove the provenance of data that they collected from an
employee, that originated in a passport -- and the assurance associated
with the employment credential, for those attributes, can be as strong as
it was for data directly from the passport itself, instead of being
governed by whatever trust someone might be inclined to give to the small
and unfamiliar employer).

This is discussed at length in Aries RFC 0104:

On Tue, Feb 18, 2020 at 11:06 AM Joe Andrieu <joe@legreq.com> wrote:

> Here's a link to the powerpoint for today's tech talk.
> https://github.com/w3c-ccg/meetings/blob/gh-pages/2020-02-18/credentials_and_capabilities.pptx?raw=true
> -j
> --
> Joe Andrieu, PMP
>                    joe@legreq.com
>    +1(805)705-8651
> Do what matters.
>                  http://legreq.com <http://www.legendaryrequirements.com>
Received on Tuesday, 18 February 2020 18:52:55 UTC

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