Mobile Driver's License Presentation

Full Title or Meme

Mobile Driver's License Presentation maps ISO 18013-5 wallet presentation to DIF Presentation Exchange.

Context

• The DIF Presentation Exchange is looking for test cases. This is such a test case (ie a use case with teeth).
• This use case looks at the wallet as the source of Presentation Statements, which is not necessarily the full scope of the DIF WG.

Actors

• Holder = The entity that submits proofs to a Verifier to satisfy the requirements described in a Presentation Definition (may or may not be the subject)
• mDL holder = individual to whom an mDL is issued = legitimate holder of the driving privileges reflected on an mDL = subject of the mDL
• Device = smartphone or similar with a trusted wallet (in the ISO docs this is conflated with the doc that resides on the device (aka mdoc)
• Verifier = The entity that defines what proofs they require from a Holder (via a Presentation Definition) in order to proceed with an interaction.
• mDL verifier = entity using an mDL reader to verify an mDL
• Issuing Authority = trusted signer of data elements
• Trust Authority = TBD source of certs

Transaction

1. The holder and verifier establish a session
2. The verifier asks for mDL data
3. mDL send data by value or by reference
4. The verifier may or may not request other data

• Transport can be by various NFC or QR code.
• Format is CBOR - represented here as json.

Security

data	mDL	DIF	Comments
Encryption	Encrypting with authentication of the mdoc requests and mdoc responses protects mdoc data from eavesdropping and alteration.	out-of-scope	it is not clear how mDL protection of alteration is meant to work
session keys	standard ephemeral key ECDH to establish session keys	out-of-scope	etc...
Reader <-> Trust authority	TLS	out-of-scope	etc..
Reader <-> Holder	exchange engagement information (see below)	assurances as to the provenance, identity, or status of a Presentation Definition from digital signatures may be required	DIF seems to be voluntary with no way for holder to make requirements known.
channel	off-line or on-line (OIDC or WebAPI) mDL reader receives the token and URL from the mDL accesses data from issuing authority	on-line only -- channel left open	etc..
privacy	supports selective release -- device always stays in user possession	not addressed	etc..

Device Engagement

data	mDL	DIF	Comments
Version	taster	unkown	etc...
Device request	The point of this piece is the assurance that the device is trustworthy	Presentation Request	etc...
Device and protocol information	tDevice, server and protocol information	not defined	etc...
Security	cipher suite and key info	open	etc..

Request

data	mDL	DIF	Comments
Device request	The point of this piece is the assurance that the device is trustworthy	Presentation Request	etc...
version	tstr	DIF information	etc...
Security	encrypted path	open	etc..

DIF Example

{
  "id": "drivers_license_information",
  "name": "Fred's Bar and Grill",
  "purpose": "Proof of age",
  "metadata": {
    "client_id": "4fb540be-3a7f-0b47-bb37-3821bd766ed4",
    "redirect_uri": "https://yourwatchful.gov/verify"
  },
  "schema": [
    {
      "uri": "https://yourwatchful.gov/drivers-license-schema.json",
      "required": true
    }
  ],
  "constraints": {
    "fields": [
      {
        "path": ["$.expirationDate"],
        "filter": {
          "type": "string",
          "format": "date-time",
          "min": "2020-12-31T23:59:59.000Z"
        }
      }
    ]
  }
}

Reference

• GitHub issues of the Presentation Exchange.