--- title: "03) Day 1. Understanding DIDs" header: teaser: /images/understanding-dids.png ---
Understanding
Decentralized Identifiers
Kim Hamilton Duffy
CTO Learning Machine
Co-chair W3C Credentials Community Group
Decentralized Identity Foundation Steering Committee
1
What is a Decentralized Identifier?
A new type of URL that is:
●
globally unique,
●
highly available,
●
persistent
●
cryptographically verifiable, and
●
does not require a central admin
2
did:btcr:txtest1:8kyt-fzzq-qqqq-ase0-d8
We use DIDs in Verifiable Credentials
3
DID Implementations (Methods)
4
did:example:123456789abcdefghijk
Scheme
DID
Method
DID Method Specific String
did:v1:nym:BcNkgGmGEpCGSJSMPB4BvWvwVM6YeTR52BSWcZTbzU23
did:btcr:txtest1:8kyt-fzzq-qqqq-ase0-d8
Examples:
DIDs Resolve to DID Documents
5
{
"@context": "https://w3id.org/veres-one/v1",
"id": "did:v1:nym:DwkYwcoyUXHNkpj3whn4DgXB4fcg9gj95vKxYN2apkZD",
"authentication": [{
"type": "Ed25519SignatureAuthentication2018",
"publicKey": [{
"id": "did:v1:test:nym:DwkYwcoyUXHNkpj3whn4DgXB4fcg9gj95vKxYN2apkZD#authn -key-1",
"type": "Ed25519VerificationKey2018",
"controller": "did:v1:nym:DwkYwcoyUXHNkpj3whn4DgXB4fcg9gj95vKxYN2apkZD",
"publicKeyBase58": "DwkYwcoyUXHNkpj3whn4DgXB4fcg9gj95vKxYN2apkZD"
}]
}],
"service": [{
"type": "ExampleMessagingService2018",
"serviceEndpoint": ”https://example.com/services/messages”
}],
… more DID-specific information here …
}
1. Authentication Mechanisms
3. Service Discovery
2. Public Key Material
did:btcr:xkyt-fzgq-qq87-xnhn
Universal Resolver
DID RESOLUTION
DID Method Spec
DID Document
DID
{
"@context": "https://w3id.org/did/v1",
"id": "did:example:123456789abcdefghi",
"publicKey": [{
"id": "did:example:123456789abcdefghi#keys-1",
"type": "RsaSigningKey2018",
"owner": "did:example:123456789abcdefghi",
"publicKeyPem": "-----BEGIN PUBLIC KEY...END PUBLIC KEY-----\r\n"
}],
"authentication": [{
"type": "RsaSignatureAuthentication2018",
"publicKey": "did:example:123456789abcdefghi#keys-1"
}],
"service": [{
"type": "ExampleService",
"serviceEndpoint": "https://example.com/endpoint/8377464"
}],
"created": "2002-10-10T17:00:00Z",
"updated": "2016-10-17T02:41:00Z",
"signature": {
"type": "RsaSignature2016",
"created": "2016-02-08T16:02:20Z",
"creator": "did:sov:8uQhQMGzWxR8vw5P3UWH1j#key/1",
"signatureValue": "IOmA4R7TfhkYTYW87z640O3GYFldw0
yqie9Wl1kZ5OBYNAKOwG5uOsPRK8/2
C4STOWF+83cMcbZ3CBMq2/gi25s=“
}
}
}
DID DOCUMENT
1. DID (for self-description)
2. Public keys (for verification)
3. Auth methods (for authentication)
4. Service endpoints (for interaction)
5. Timestamp (for audit history)
6. Signature (for integrity)
Status
8
● Incubated at RWOT, IIW
● Currently:
○ Draft report in W3C Credentials Community
Group
○ Protocols and prototypes at DIF
○ DID Method Registry
○ DID Auth, DID Resolver
● To Discuss: DID Working Group
DID & VC Architecture
Roadmap 2018+
Christopher Allen
Principal Architect & Founder — Blockchain Commons
W3C Credentials CG Chair
9
Current W3C Standards Track Efforts
10
● Verifiable Claims WG, Verifiable Credentials
○ Anyone can verifiably say anything about anyone.
○ Identity emerges from evaluating multiple sources of
information, across multiple interactions
● Decentralized Identifiers (DIDs), draft WG
○ Anyone can publicly manage provable identifiers without
administrative interference
○ Move beyond centrally administered IDs
○ Provide for a plurality of authorities
Decentralized Identity Stack
11
● DIDs – Root Identifiers
○ DID Universal Resolvers — support interoperability between
multiple DID methods.
○ DID Methods – Specific approaches using different blockchains
○ DID Documents – Proof of Control & Service References
+
Decentralized Identity Stack
12
● DIDs – Root Identifiers …
● Raw Data – Observed facts & transactions
● Verifiable Credentials – Assertions by knowable authorities
● Profiles / Presentations / Persona – Representations of individuals
● Consent – Records of authorization
● Reasoning – Interpretation & Analysis
● Evaluation – Risk Analysis & Reputation
● Understanding – Internal knowledge representation
● Services – Interactions of value
Potential Standards for Future Work
13
● DID-Auth (Authn/Authz)
● OCAP (Authz through Object Capabilities)
● Credential Requests & Exchange
● Data Minimization & Selective Disclosure
● Consent & Consent Receipts
● Storage (Identity Hubs) & Internal Representations
● Analytics & Algorithms for Evaluation
● Cryptographic Proofs
○ Signature, Encryption, Signcryption Suites
○ Time-stamping
○ Zero-knowledge proofs
https://w3c-ccg.github.io/roadmap/diagram.html