W3C home > Mailing lists > Public > public-credentials@w3.org > June 2017

Re: creator prefix scheme in Koblitz signature specification

From: Nate Otto <nate@ottonomy.net>
Date: Fri, 2 Jun 2017 16:12:52 -0700
Message-ID: <CAPk0ug=vzaBbE118E+WV6kLKP6Z7-jFC8OJjGcOwkms1_qZbtQ@mail.gmail.com>
To: Kim Hamilton Duffy <kim@learningmachine.com>
Cc: "W3C Credentials CG (Public List)" <public-credentials@w3.org>, Manu Sporny <msporny@digitalbazaar.com>
Here's what I see for documentation around the Key class.

The @id is prototypically an HTTP(s) URI. It seems that this
ecdsa-koblitz-pubkey IRI scheme allows its value to be the entire public
key, so that if you have an ID in this format, you can verify signatures
created by the keypair. The (RSA, etc) keys that the Key class was designed
for don't seem to have this capability. That is why the Key class has
a publicKeyPem property, because PEM is a format that these keys may be
expressed in.

I imagine you could use the Key class with a ecdsa-koblitz-pubkey @id if
you wanted to express this Key and metadata about it.

  "@context": "https://w3id.org/security/v1",
  "@id": "ecdsa-koblitz-pubkey:abc123",
  "@type": "Key",
  "owner": "https://payswarm.example.com/i/bob",}

The advantage of the Key class having an HTTP(s) @id is that it may be
retrieved easily by many different clients. One can create a 2-way link
between a specific Key file and a specific owner entity.  For example, an
Open Badges Profile <https://w3id.org/openbadges#Profile> (
https://w3id.org/openbadges#Profile ) has a "sec:publicKey" property that
points to a Key instance, which points back to the Profile as its "owner".

To achieve the same with an ecdsa-koblitz-pubkey scheme @id you could just
put the string as the value of the "sec:publicKey" property (which expect
an @id-type value) in documents that are trusted by your audience to
describe the key owner. I don't really see any changes to make here to the
Key class.

If anything, I'm more concerned that I don't know how an IRI scheme like
ecdsa-koblitz-pubkey is standardized so that we can know when it is stable
and ready to build implementations against.

Nate Otto
Director, Open Badges, Concentric Sky
Received on Friday, 2 June 2017 23:13:27 UTC

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