Markus Sabadello
Danube Tech, DIF, Sovrin,
W3C CCG, W3C VCWG, OASIS XDI TC
https://danubetech.com/
W3C Workshop on Strong Authentication & Identification
Redmond, WA, USA – 10
th
December 2018
DID Auth
■ Background
● Decentralized Identifiers (DIDs)
● Decentralized Public Key Infrastructure (DPKI)
■ DID Auth
● Prove that the DID subject controls its DID
● A concept, with different architectures and implementations
DID Document
■ DID Document tells us how control of the DID can be proven
■ DID Document contains service endpoints, public keys, authentication
methods
{
"@context": "https://w3id.org/did/v1",
"id": "did:sov:WRfXPg8dantKVubE3HX8pw",
"service": {
"type": "hub",
"serviceEndpoint": "https://azure.microsoft.com/dif/hub/did:sov:WRfXPg8dantKVubE3H"
},
"publicKey": [
{
"id": "did:sov:WRfXPg8dantKVubE3HX8pw#key-1",
"type": "Ed25519VerificationKey2018",
"publicKeyBase58": "H3C2AVvLMv6gmMNam3uVAjZpfkcJCwDmqPV"
}
],
"authentication": {
"type": "Ed25519SignatureAuthentication2018",
"publicKey": [
"did:sov:WRfXPg8dantKVubE3HX8pw#key-1"
]
}
}
DID Document
■ DID Document tells us how control of the DID can be proven
■ DID Document contains service endpoints, public keys, authentication
methods
{
"@context": "https://w3id.org/did/v1",
"id": "did:sov:WRfXPg8dantKVubE3HX8pw",
"service": {
"type": "hub",
"serviceEndpoint": "https://azure.microsoft.com/dif/hub/did:sov:WRfXPg8dantKVubE3H"
},
"publicKey": [
{
"id": "did:sov:WRfXPg8dantKVubE3HX8pw#key-1",
"type": "Ed25519VerificationKey2018",
"publicKeyBase58": "H3C2AVvLMv6gmMNam3uVAjZpfkcJCwDmqPV"
}
],
"authentication": {
"type": "Ed25519SignatureAuthentication2018",
"publicKey": [
"did:sov:WRfXPg8dantKVubE3HX8pw#key-1"
]
}
}
DID Auth Example Architecture
Challenges, Responses, Transports
■ Challenge-response flow to prove that the DID subject controls its DID.
■ Transports: HTTP POST, QR code, Mobile deep link, JavaScript browser
API, Bluetooth, NFC, etc.
■ Transports may require additional information such as endpoint URIs that
may be included in the challenge, or discoverable from a DID.
■ Challenge:
● Identity owner’s DID may or not be
known.
● May or may not contain proof of control
of a DID of the relying party.
■ Response:
● Linked to a challenge (e.g. using a
nonce).
● Contains proof of control of a DID of the
identity owner.
DID Auth Example Architectures
DID Auth Data Formats
■
Example JWT:
■ Example JSON-LD VC:
{
"header": {
"typ": "JWT",
"alg": "ES256"
},
"payload": {
"iss":
"did:example:123456789abcdefg",
"sub":
"did:example:123456789abcdefg",
"iat": 1479850830,
"exp": 1511305200,
},
"signature": "..."
}
{
"type": ["Credential"],
"issuer": "did:example:123456789abcdefg",
"issued": "2018-03-07",
"credentialSubject": {
"id": "did:example:123456789abcdefg",
"publicKey": "did:example:123456789abcdefg#ke
},
"proof": {
"type": "Ed25519Signature2018",
"created": "2018-01-01T21:19:10Z",
"creator": "did:example:123456789abcdefg#keys
"nonce": "c0ae1c8e-c7e7-469f-b252-86e6a0
"signatureValue": "..."
}
}
DID Auth Data Formats
■
Example JWT:
■ Example JSON-LD VC:
{
"header": {
"typ": "JWT",
"alg": "ES256"
},
"payload": {
"iss":
"did:example:123456789abcdefg",
"sub":
"did:example:123456789abcdefg",
"iat": 1479850830,
"exp": 1511305200,
},
"signature": "..."
}
{
"type": ["Credential"],
"issuer": "did:example:123456789abcdefg",
"issued": "2018-03-07",
"credentialSubject": {
"id": "did:example:123456789abcdefg",
"publicKey": "did:example:123456789abcdefg#ke
},
"proof": {
"type": "Ed25519Signature2018",
"created": "2018-01-01T21:19:10Z",
"creator": "did:example:123456789abcdefg#keys
"nonce": "c0ae1c8e-c7e7-469f-b252-86e6a0
"signatureValue": "..."
}
}
Relation to OIDC, WebAuthn
■
OIDC + DID
● Self-Issued OpenID Provider
● Discover OIDC endpoint from DID
■ WebAuthn + DID
● Registration
Register(Account, Origin)
● Registration Response (without DID)
RegisterResponse(PublicKeyCredential,
Attestation, Origin)
● Registration Response (with DID)
RegisterResponse(DIDCredential,
Attestation, Origin)
{
"@context": "https://w3id.org/did/v1",
"id": "did:example:123456789abcdefg",
"service": [{
"id": "did:example:123456789abcdefg;openid",
"type": "OpenIdConnectVersion1.0Service",
"serviceEndpoint": "https://openid.example.com/"
}]
}
■ And more! DID-TLS, DID-HTTP-Signatures, DID-PGP, DID-
SSH
For the Workshop
■ Come up with a list of core DID Auth principles
1) The identifier that is being authenticated is a DID.
2) All elements of the DID Document can change, the DID stays the same.
3) DID Resolution is performed to discover how to authenticate the DID.
4) … more?
■ Workshop Question #1: Relation to OIDC, FIDO, WebAuthn?
■ Workshop Question #2: Relation to VC exchange protocols?
Community Resources
■ W3C Credentials Community Group
https://www.w3.org/community/credentials/
■ Decentralized Identity Foundation
http://identity.foundation/
■ Rebooting-the-Web-of-Trust
http://www.weboftrust.info/
■ Internet Identity Workshop
http://internetidentityworkshop.com/
Thank You
■ Markus Sabadello
■ Danube Tech
https://danubetech.com/
■ markus@danubetech.com
z
Backup Slides
Rebooting-the-Web-of-Trust
Internet Identity Workshop
DIDs: W3C Credentials CG
v0.11 Draft Community Report
DIDs: W3C DID WG
Charter now being written
Yadis, XRI, XRD, XRDS,
JRD, Webfinger
DID registered
prov. URI scheme
DID method specs
W3C Web Payments CG
OASIS XDI TC
W3C JSON-LD 1.1
W3C Cryptographic Suites
RFC 7517: JWK
Verifiable Credentials
DKMS, DID Auth
Hubs, Agents, XDI
DID Universal Resolver
■ Looks up (“resolves”) DID to its
DID Document.
■ Provides a universal API that works
with all DID methods.
■ Uses a set of configurable “drivers”
that know how to connect to the
target system.
■ https://uniresolver.io/
