Re: Interop meeting - today

Kai Wagner

Hello Taylor, @all

thank you very much for picking up the "define interop" discussion again.

At Jolocom, we have been thinking about this for a long time and it is one of our main decision making factor as we move on in developing our SSI technology.

While I hear the points made by Daniel Hardman on building interop only where relevant populations are present, I can not agree with it. In fact, the approach described by Daniel might even lead to a discussion on compatibility, rather than interoperability (see wikipedia citation below).

"interoperability imply Open standards ab-initio, i.e. by definition. Interoperability implies exchanges between a range of products, or similar products from several different vendors, or even between past and future revisions of the same product. Interoperability may be developed post-facto, as a special measure between two products, while excluding the rest, by using Open standards. When a vendor is forced to adapt its system to a dominant system that is not based on Open standards, it is not interoperability but only compatibility."

At Jolocom, we have defined interoperability like this:

"All agents / participants can communicate and interact with each other directly, without intermediaries, regardless of the agent / wallet implementations being used. The participants do so by supporting a common set of interfaces, and communicating using open and well-established specifications. Ideally this communication should not be facilitated by a 3rd party provided / maintained infrastructure, as this bears the risk of a lock in effect and centralization of the larger infrastructure."

With this definition as a starting point, we have tried to operationalize interoperability by describing the result of interop in the following statements:

  • As an Issuer/Verifier I can present one QR code to request interactions, regardless of what wallet/agent is on the other end (I never have to care).
  • As an identity subject/holder I can use any wallet I want, I can move across wallets, including encrypted backups.
  • An identity Holder can present a Verifiable Credential to a Verifier, regardless of which implementation the verifier or issuer uses, or which wallet the Holder uses.
  • As a Verifier, I can resolve DIDs from any DID method and use the DID Document to verify signatures, regardless of which DID method the document is from.
  • As a Verifier, I can check the integrity of the Credential regardless of the implementation used by the issuer of that credential as well as the holder.
  • As a developer, I can use any implementation of SSI tools (i.e. libraries, CLI tools) and expect it to perform its role with other deployments.

The above points are only a start and feedback is much welcomed. Ultimately, we think the discussion on interop need to lead to a modular and open ecosystem where interoperability is achieved by following standards and specifications, rather that "welding things together", which is handled in a "different IIW community".

I hope we can bring the interop-working group to work in that direction.

Looking forward to your thoughts and ideas.



Kai Wagner
Partnership Development

+49 176 83 588 604

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Jolocom GmbH, Waldemarstrasse 37A, 10999 Berlin, Germany
CEO (Geschäftsführer): Joachim Lokhamp
Amtsgericht Charlottenburg (Berlin): HRB 158758 B
Am 29.07.20 um 17:07 schrieb Taylor Kendal:
As follow-on to the “define interop” discussion. 

Is it possible/reasonable to land on a common denominator (highest level possible) which could broaden/narrow based on groups represented?

The ability of a system to work with or use the component parts of another system.

Or a bit more specific:

The ability for different systems, devices or applications to connect, in a coordinated manner, within and across organizational boundaries to access, exchange and cooperatively use data amongst stakeholders.

Then the inevitable moving targets fall under various sub-domains (foundational, structural, semantic, organizational, etc.) 

Also, as far as “outputs,” I think there’s intangible value in simply having a neutral venue for building/sharing context. 
*Recommended practice: join DIF interop wg :)

Food for thought...

Taylor Kendal, CPO

From: Balázs Némethi <balazs@...>
Sent: Wednesday, July 29, 2020 6:00:39 AM
To: <>
Subject: Interop meeting - today
Dear all,

A few reminders about today's meeting and next week's:
  • The nomination of chairs will close - if you have not, please nominate using this form
  • Election of chairs will happen over email.  You'll receive information after the meeting
  • It will be open for one week
  • Ballots will be checked against the attendance records of this group: 2 of the last four meetings when ballots close, i.e., last two meetings, today, and next week's.
  • During today's meeting, we'll do a little more issue review on the charter, a little discussion of the ballot, and the rest of the time will be to discuss workitems and roadmap
Best regards,

Balázs Némethi
Operations @ DIF

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