RE: DID Use Case: Public Pointers to Private Data

Any technology has dependencies on a variety of things including infrastructure.
Technical infrastructure has a dependency on developers, maintainers, providers and operators of that infrastructure.
There are a variety of risks that are introduced by those entities and those in turn can be mitigated using a variety of techniques, not all of them technical.

However, while there has been an articulation of the “Principles of Self-Sovereign Identity” [1], has there been a Threat Model that has been developed that has broad agreement by the folks who are championing the SSI movement?

Best Regards,

-          Anil

[1] http://www.lifewithalacrity.com/2016/04/the-path-to-self-soverereign-identity.html



From: Chris Boscolo <chris@boscolo.net>
Sent: Monday, June 18, 2018 4:26 PM
To: W3C Credentials CG <public-credentials@w3.org>
Subject: Re: DID Use Case: Public Pointers to Private Data

I think Anil has highlighted what may end up being the Achilles' heel for DID-based SSI adoption.

For this SSI system to remain decentralized and free from censorship, the software that looks up the DID Documents for DIDs contained within Verified Credentials must be able to communicate directly with the distributed ledger that contains the DID Documents.

This means the software that process Verified Credentials must support ALL DID methods it ever expects to encounter, OR it must rely on some yet-to-be-defined way to dynamically “load” support for newly encountered DID methods.  All other means to address this that I have read about re-introduce centralization.  It will be nearly impossible to introduce new DID methods into the ecosystem because it will require everyone that processes VCs to update the software to support the new DID method.

Open-source efforts like the DIF universal resolver are important for interop testing of the DID Document lookup and processing but don't solve the "centralization" problem.

Does anyone else in this community think this is a legitimate concern?  If so, perhaps we could discuss ways to bridge the gap between now and market adoption.

   -chrisb


On Wed, Jun 13, 2018 at 7:58 AM, =Drummond Reed <drummond.reed@evernym.com<mailto:drummond.reed@evernym.com>> wrote:
On Wed, Jun 13, 2018 at 6:59 AM, John, Anil <anil.john@hq.dhs.gov<mailto:anil.john@hq.dhs.gov>> wrote:
Thanks Drummond.

So the magic thingy needed to make this work is a DID resolver and an existing product/system will need be upgraded in order to have this network discovery ability.

Yes.


Who, if anyone, is building an open source, royalty free, and free to use SDK that contains this functionality that existing technology providers can then integrate with their tech stack?

The DIF universal resolver is being designed for this. And the Hyperledger Indy SDK should also have this capability.


If the intent is to provide this capability as a service offering, what would be the business model around that offering that is both long term sustainable and prevents platform lock-in?

Ironically I believe DID registration and resolution will rapidly become a commodity similar to DNS registration except: a) decentralized, and b) at dramatically lower cost (pennies or fractions of pennies instead of dollars). So sustainability will be at the public or private blockchain level, which has entirely different economics (and, of course, a much stronger security and privacy model, since crypto is baked in at the very core).

Best,

=Drummond


Best Regards,

-          Anil

From: =Drummond Reed <drummond.reed@evernym.com<mailto:drummond.reed@evernym.com>>
Sent: Wednesday, June 13, 2018 9:24 AM

To: John, Anil <anil.john@hq.dhs.gov<mailto:anil.john@hq.dhs.gov>>
Cc: W3C Credentials CG <public-credentials@w3.org<mailto:public-credentials@w3.org>>
Subject: Re: DID Use Case: Public Pointers to Private Data

On Wed, Jun 13, 2018 at 6:08 AM, John, Anil <anil.john@hq.dhs.gov<mailto:anil.john@hq.dhs.gov>> wrote:
>I have always felt the line is quite clear: there is the DID layer of interoperability,

Could you explain what interoperability at the DID layer means?

Just that any peer can use a DID resolver to look up the DID document for any other peer. I often use the analogy (which is just an analogy) that it's the decentralized cryptographic equivalent of DNS.


>and then the "decentralized P2P protocol" level of interop,
>i.e., the protocol that any two DID-identified peers can use to talk.

I assume that one is not tied to the other? i.e. After bootstrapping from what a DID provides, I can use existing protocols and data definition standards for two systems to talk w/ each other?

Absolutely. That's the purpose of the service endpoint block in the DID document. Any peer can advertise the endpoint(s) and protocol(s) it supports in its DID document.


In an Enterprise setting with existing technology and process investments that need to be leveraged, adding in a light-weight (DID) layer that serves as an introduction/matching/brokering capability between disparate systems would be of value if that is a core capability baked into the DID specification rather than outside of it.

I think that's just what we have baked in. If you find anything missing, let us know and we'll fix it.

Best,

=Drummond


Best Regards,

-          Anil

From: =Drummond Reed <drummond.reed@evernym.com<mailto:drummond.reed@evernym.com>>
Sent: Wednesday, June 13, 2018 7:56 AM

To: John, Anil <anil.john@hq.dhs.gov<mailto:anil.john@hq.dhs.gov>>
Cc: W3C Credentials CG <public-credentials@w3.org<mailto:public-credentials@w3.org>>
Subject: Re: DID Use Case: Public Pointers to Private Data

On Wed, Jun 13, 2018 at 4:21 AM, John, Anil <anil.john@hq.dhs.gov<mailto:anil.john@hq.dhs.gov>> wrote:
I had help to sanity check my intent : -)

Your mention of the ‘sovrin protocol’ also brings to light one of my concerns in this area which is that there needs to be careful thought given to what is part and parcel of the base DID spec and what is spun out to be the responsibilities of DID enabled implementations like Sovrin or Veres One or others.

I have always felt the line is quite clear: there is the DID layer of interoperability, and then the "decentralized P2P protocol" level of interop, i.e., the protocol that any two DID-identified peers can use to talk.


I am concerned that this type of design choice conversation is not happening in public, and that the standard response seems to be (1) We are thinking about ANOTHER spec for THAT or (2) It is supported in the [implementation] protocol.

The Sovrin protocol is being developed very publicly by the Sovrin Foundation<http://forum.sovrin.org/>, in part because W3C explicitly put protocol out-of-scope when it chartered the Verifiable Claims Working Group. There are of course other open standard P2P data exchange protocols that could be used, including UMA and OASIS XDI, but neither of those has been focused directly on the nuances of verifiable claims exchange, and in particular using zero-knowledge proofs for selective disclosure. That's the focus of the Sovrin protocol, the standard implementation of which is available as open source code in Hyperledger Indy<https://chat.hyperledger.org/channel/indy-agent>.

Best,

=Drummond


Best Regards,

-          Anil

From: =Drummond Reed <drummond.reed@evernym.com<mailto:drummond.reed@evernym.com>>
Sent: Wednesday, June 13, 2018 12:09 AM
To: John, Anil <anil.john@hq.dhs.gov<mailto:anil.john@hq.dhs.gov>>
Cc: W3C Credentials CG <public-credentials@w3.org<mailto:public-credentials@w3.org>>
Subject: Re: DID Use Case: Public Pointers to Private Data

Anil, this is beautifully stated. I'll note that within the Sovrin ecosystem, standardizing how access to a resource can obtained via a Sovrin agent endpoint listed in a DID document is one of the primary purposes of the Sovrin protocol<https://github.com/sovrin-foundation/protocol>. The authorization method is of course based on verifiable credentials. Much work is still to be done, but you have stated the need, the challenge, and the distinction of the work very well.

=D

On Tue, Jun 12, 2018 at 11:59 AM, John, Anil <anil.john@hq.dhs.gov<mailto:anil.john@hq.dhs.gov>> wrote:

Name

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Public Pointers to Private Data





Background

-------------------

When sharing information between multiple organizations, each participant typically segregates data that is publicly visible from data that is considered private. It is useful for organizations to provide the public information in a way that is cryptographically verifiable and includes the ability to point to data stores containing associated private information. This private information should only be accessible to authorized entities on an automated, case by case basis.





Need

--------------------

A national customs and border authority facilitating and enforcing the movement of goods across its border is automating and streamlining the sharing of relevant documentation from trade organizations. The customs authority asks each trade organization to self-issue an identifier that enables them to create digital signatures for the purposes of signing documentation and authenticating themselves. When a trade organization ships goods across the border, it uses the identifier to digitally sign and share data that is visible to the customs authority and other trade members. When and what data was provided by the trade organization is auditable, including pointers to private, trade-sensitive, access controlled data. When the customs authority is performing an inspection, (a) it reads and verifies the public data and private pointers, (b) retrieves a cryptographic access token that only they can use to access the private data, and (c) accesses the private data using the cryptographic access token.





Challenge

-------------------

While the public records are accessible to the customs authority and the trade organizations, the private records are only accessible to the customs authority or someone that they delegate the access token to. There are three protocols at play here: (1) accessing the public records, (2) using the access token for private access, and (3) the mechanism used to authenticate during the private access and the subsequent authorization to see the relevant private data.





Distinction

-------------------

This use case identifies the notion that DIDs and DID Documents will enable architectural models and protocols that have a public and private component to them. The identification of each actor in the ecosystem and all three protocols in the challenge  are dependent on the authentication and authorization mechanisms supported/referenced by DIDs and DID Documents.



This use case also suggests that naturally delegatable authentication and authorization mechanisms should be considered in order to reduce operational overhead and avoid privilege escalation problems when accessing these private systems.


Best Regards,

-          Anil

Anil John
Cyber Security R&D Program Manager
Science and Technology Directorate
US Department of Homeland Security
Washington, DC, USA
anil.john@hq.dhs.gov<mailto:anil.john@hq.dhs.gov>

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