Re: Verifiable Text-based Claims

David,

Thank you. Supersession is described in more detail here: https://w3c-ccg.github.io/verifiable-news/sketchpad.html#supersession-of-statements . Though it differs from revocation, I’m thinking that, since supersession extends revocation, a supersession object could be at a URL indicated for a revocation object, providing additional information. If a system doesn’t process supersession, then it can process a supersession as a revocation, and, if a system does process supersession, then it obtains the additional information.

Here is an updated version:

{
  "id": "https://example.com/users/1/revocations/ebfeb1f712ebc6f1/",
  "type": ["Revocation", "Supersession"],
  "issuer": "https://example.com/users/1/issuer/",
  "issued": "2017-06-19T21:19:10Z",
  "revoked": "https://example.com/facts/ebfeb1f712ebc6f1/",
  "supersededBy": "https://example.com/facts/a3cc92841ac9c3f2/",
  "reason": {
    "id": "https://example.com/users/1/rationale/a3cc92841ac9c3f2/",
    "type": "HTMLEmbeddedRationale"
  },
  "signature": {
    "type": "LinkedDataSignature2017",
    "created": "2017-06-19T21:19:10Z",
    "creator": "https://example.com/users/1/keys/",
    "nonce": "c0ae1c8e-c7e7-469f-b252-86e6a0e7387e",
    "signatureValue": "BavEll0/I1zpYw8XNi1bgVg/sCneO4Jugez8RwDg/+MCR
    VpjOboDoe4SxxKjkCOvKiCHGDvc4krqi6Z1n0UfqzxGfmatCuFibcC1wpsPRdW+g
    GsutPTLzvueMWmFhwYmfIFpbBu95t501+rSLHIEuujM/+PXr9Cky6Ed+W3JT24="
  }
}

I’m still considering whether the features and expressiveness are worth the additional complexity.


Best regards,
Adam

From: David Chadwick<mailto:D.W.Chadwick@kent.ac.uk>
Sent: ‎Saturday‎, ‎September‎ ‎16‎, ‎2017 ‎1‎:‎57‎ ‎PM
To: Adam Sobieski<mailto:adamsobieski@hotmail.com>, public-credentials@w3.org<mailto:public-credentials@w3.org>



On 15/09/2017 15:27, Adam Sobieski wrote:
> David,
>
> I see your point. I was thinking about the special case of journalistic
> retractions. I updated the example indicating a revocation object.
>
> I’m thinking that we can also use revocations for superseding
> statements, which allows features including the updating of and the
> moving/redirection of statements.

This is conceptually something different from a revocation statement.
Consequently I would suggest that the original statement is revoked and
a new statement is issued.

regards

David

>
> {
>   "id":"https://example.com/users/1/revocations/ebfeb1f712ebc6f1/",
>   "type":"Revocation",
>   "issuer":"https://example.com/users/1/issuer/",
>   "issued":"2017-06-19T21:19:10Z",
>   "revoked":"https://example.com/facts/ebfeb1f712ebc6f1/",
>   "supersededBy": "https://example.com/facts/a3cc92841ac9c3f2/"
>   "signature":{
>     "type":"LinkedDataSignature2017",
>     "created":"2017-06-19T21:19:10Z",
>     "creator":"https://example.com/users/1/keys/",
>     "nonce":"c0ae1c8e-c7e7-469f-b252-86e6a0e7387e",
>     "signatureValue":"BavEll0/I1zpYw8XNi1bgVg/sCneO4Jugez8RwDg/+MCR
>     VpjOboDoe4SxxKjkCOvKiCHGDvc4krqi6Z1n0UfqzxGfmatCuFibcC1wpsPRdW+g
>     GsutPTLzvueMWmFhwYmfIFpbBu95t501+rSLHIEuujM/+PXr9Cky6Ed+W3JT24="
>   }
> }
>
>
> Best regards,
> Adam
>
> *From:* David Chadwick <mailto:D.W.Chadwick@kent.ac.uk>
> *Sent:* ‎Friday‎, ‎September‎ ‎15‎, ‎2017 ‎5‎:‎51‎ ‎AM
> *To:* Adam Sobieski <mailto:adamsobieski@hotmail.com>,
> public-credentials@w3.org <mailto:public-credentials@w3.org>
>
> Hi Adam
>
> the revocation statement should not contain details of the VC that has
> been revoked as this is privacy invasive. There are no ACLs on
> revocation lists (usually). All it should contain is the ID of the VC
> that has been revoked, signed by the issuer (in a similar way to an
> X.509 CRL). In this was an inspector who has the VC, has the unique ID
> and can therefore check if the VC was revoked or not
>
> regards
>
> David
>
> On 15/09/2017 02:52, Adam Sobieski wrote:
>> David,
>>
>> Updated the sketchpad per your recommendation:
>>
> https://w3c-ccg.github.io/verifiable-news/sketchpad.html#revocation-of-statements .
>>
>>
>> Best regards,
>> Adam
>>
>> *From:* David Chadwick <mailto:D.W.Chadwick@kent.ac.uk>
>> *Sent:* ‎Thursday‎, ‎September‎ ‎14‎, ‎2017 ‎6‎:‎33‎ ‎PM
>> *To:* public-credentials@w3.org <mailto:public-credentials@w3.org>
>>
>> Hi Adam
>>
>> On 14/09/2017 02:50, Adam Sobieski wrote:
>>> David,
>>>
>>> Thank you. At
>>>
>>
> https://w3c-ccg.github.io/verifiable-news/sketchpad.html#http-based-revocation ,
>>> I describe a system where Not found (404, 410) means revoked and Ok
>>> (200) means not revoked. I see what you’re saying about Not found
>>> meaning not revoked and Ok with a credential ID meaning revoked as well
>>> as the feature of retrieving lists of revoked credentials. I think that
>>> we should have both HTTP-based approaches. I updated the document with
>>> these ideas.
>>>
>>
>> In order to make the revocation more secure we placed a digitally signed
>> CRL at the revoke URL. In this way a hacker is not able to hack the web
>> site and get it to return OK with a message, because he does not have
>> access to the issuer's private key
>>
>> regards
>>
>> David
>>>
>>> Best regards,
>>> Adam
>>>
>>> *From:* David Chadwick <mailto:D.W.Chadwick@kent.ac.uk>
>>> *Sent:* ‎Wednesday‎, ‎September‎ ‎13‎, ‎2017 ‎3‎:‎21‎ ‎PM
>>> *To:* public-credentials@w3.org <mailto:public-credentials@w3.org>
>>>
>>> Hi Adam
>>>
>>> I notice that you are also including a revocation mechanism in your
>>> claims. I produced an IETF draft 10 years ago which proposed something
>>> very similar for X.509 certificates
>>> ( See https://www.ietf.org/archive/id/draft-chadwick-webdav-00.txt).
>>> Conceptually they are the same: the credential contains the URL where
>>> the revocation information can be found. If Not found is returned the
>>> credential has not been revoked, otherwise Ok is returned along with a
>>> CRL of length 1 containing the ID of the revoked credential. My ID
>>> contains other features as well, such as the ability to retrieve all the
>>> revoked credentials of a particular issuer. You might wish to consider
>>> this as well
>>>
>>> regards
>>>
>>> David
>>>
>>> On 12/09/2017 22:13, Adam Sobieski wrote:
>>>> I’m exploring and sketching some ideas with regard to verifiable
>>>> text-based claims.
>>>>
>>>> https://w3c-ccg.github.io/verifiable-news/sketchpad.html

>>>>
>>>> Questions, comments and suggestions welcomed.
>>>>
>>>>
>>>> Best regards,
>>>> Adam Sobieski
>>>>
>>>
>>