did:klay

Klaytn DID Method (did:klay) is a decentralized identifier implementation built on the Klaytn blockchain platform. This method provides a straightforward approach to digital identity management by automatically associating DIDs with Klaytn blockchain addresses. The method's key feature is its implicit creation process - any address on the Klaytn blockchain automatically has an associated DID without requiring explicit registration.

The method implements a smart contract-based registry that manages DID documents and their lifecycle. Each DID is directly derived from a Klaytn address by prefixing it with did:klay:, creating a seamless connection between blockchain accounts and decentralized identifiers. This approach simplifies identity management while leveraging the security properties of the underlying blockchain.

Key capabilities include:

• Automatic DID creation tied to blockchain addresses
• Delegate management through controller assignments
• Document updates via smart contract functions
• Deactivation mechanism that permanently revokes DIDs
• Verification method management

Technical Implementation:

1. DID Generation and Structure

   • Format: did:klay:<40-character-hex-string>
   • Example: did:klay:1f4B9d871fed2dEcb2670A80237F7253DB5766De
   • Generated automatically from Klaytn addresses (without 0x prefix)

2. Resolution Process

   • Implemented through getDocument method in registry contract
   • Supports multiple resolution methods:
   • Primary resolver for complete DID documents
   • Secondary resolvers for specific properties
   • Verification through multiple node queries

3. Key Management and Security

   • Uses ECDSA secp256k1 cryptography
   • Implements EcdsaSecp256k1VerificationKey2019 verification method
   • Supports controller delegation system
   • One-to-one mapping between addresses and DIDs

4. Technical Stack

   • Built on Klaytn blockchain platform
   • Uses smart contracts for registry management
   • Implements W3C DID Core specification
   • Supports standard CRUD operations

5. Unique Features

   • Implicit DID creation without registration
   • Permanent deactivation mechanism
   • Delegate-based control system
   • Controller-based authentication management

Security Considerations:

• Single DID per Klaytn address
• Permanent deactivation without reactivation possibility
• Delegate privileges equal to DID subject
• No personal information storage in DID documents

Example DID Document:

{
  "@context": ["https://www.w3.org/ns/did/v1"],
  "id": "did:klay:1f4B9d871fed2dEcb2670A80237F7253DB5766De",
  "publicKey": [{
    "id": "did:klay:1f4B9d871fed2dEcb2670A80237F7253DB5766De#keys-1",
    "type": "EcdsaSecp256k1VerificationKey2019",
    "controller": "did:klay:1f4B9d871fed2dEcb2670A80237F7253DB5766De",
    "publicKeyHex": "0xfbf38de9fb40edcdab412094d24fa39a314f3d3f52f5860e2509c32522eda30161fe70dfc9f90434d64bd976ede4f112d4f2d8e34d28fe48281663219d2ddac6"
  }],
  "authentication": ["did:klay:1f4B9d871fed2dEcb2670A80237F7253DB5766De#keys-1"]
}