Identity SDK Reference

Canonical function reference for:

• @oma3/omatrust/identity

Core Types

type Hex = `0x${string}`;
type Did = string;
type Caip10 = string;

Error Handling

Identity functions throw OmaTrustError (extends Error) with a stable code property.

class OmaTrustError extends Error {
  code: string;
  details?: unknown;
}

Code	Thrown by	Description
INVALID_INPUT	All functions receiving malformed params	Missing required fields, wrong types
INVALID_DID	normalizeDid, normalizeDidWeb, normalizeDidPkh, normalizeDidHandle, normalizeDidKey, computeDidHash, didToAddress, validateDidAddress, all get*FromDid*	String is not a valid DID or wrong method
INVALID_CAIP	parseCaip10, normalizeCaip10, parseCaip2, buildDidPkhFromCaip10	String is not a valid CAIP-10 or CAIP-2

DID Utilities

Most developers should use normalizeDid, didToAddress, and the CAIP builders/parsers. All DID functions are pure local computation — no RPC calls.

Validation

• isValidDid(did: string): boolean — Check if a string matches the basic DID format (did:method:identifier). Does not validate method-specific rules.
• extractDidMethod(did: Did): string — Extract the method from a DID (e.g., "web" from "did:web:example.com"). Returns null if not a valid DID.
• extractDidIdentifier(did: Did): string — Extract the identifier portion (e.g., "example.com" from "did:web:example.com"). Returns null if not a valid DID.

Normalization

• normalizeDid(input: string): Did — Normalize any DID to its canonical form. Routes to the appropriate method-specific normalizer. Bare domains (no did: prefix) are treated as did:web. Throws INVALID_DID for malformed input.
• normalizeDidWeb(input: string): Did — Normalize a did:web DID. Lowercases the host, strips a leading www., removes a trailing ., and preserves path case. Throws INVALID_DID if input is a non-web DID method.
• normalizeDidPkh(input: string): Did — Normalize a did:pkh DID. Lowercases the address component per CAIP-10 canonical form. Expects format did:pkh:namespace:chainId:address. Throws INVALID_DID.
• normalizeDidHandle(input: string): Did — Normalize a did:handle DID. Lowercases the platform, preserves username case (platform-defined). Expects format did:handle:platform:username. Throws INVALID_DID.
• normalizeDidKey(input: string): Did — Normalize a did:key DID. Returns as-is (multibase encoding is case-sensitive). Throws INVALID_DID.
• normalizeDomain(domain: string): string — Normalize a domain name: lowercase, strip trailing dot, strip leading www..

Hashing and Address

• computeDidHash(did: Did): Hex — Compute the keccak256 hash of a normalized DID. Normalizes the DID first, then hashes the UTF-8 bytes. For did:web, this uses the canonical hostname form, so did:web:www.example.com and did:web:example.com hash identically. Returns a 32-byte hex string. Throws INVALID_DID.
• computeDidAddress(didHash: Hex): Hex — Compute a DID Address from a DID hash by taking the last 20 bytes (simple truncation per OMATrust spec §5.3.2). Returns lowercase 0x-prefixed hex (no EIP-55 checksum casing). This is not a real wallet address — it's a derived lookup key for EAS attestation indexing.
• didToAddress(did: Did): Hex — Convenience: normalize a DID, hash it, and return the DID Address in one call (lowercase 0x-prefixed hex). For did:web, the canonical hostname form strips a leading www. before hashing. Throws INVALID_DID.
• validateDidAddress(did: Did, address: Hex): boolean — Verify that a DID Address was computed correctly for a given DID. Returns false on any error.

DID Builders

• buildDidWeb(domain: string): Did — Build a did:web DID from a domain name (e.g., "example.com" → "did:web:example.com"). Normalizes the domain, including stripping a leading www..
• buildDidPkh(namespace: string, chainId: string | number, address: string): Did — Build a did:pkh DID from components (e.g., "eip155", 1, "0x..." → "did:pkh:eip155:1:0x..."). Lowercases the address.
• buildEvmDidPkh(chainId: string | number, address: string): Did — Convenience: build a did:pkh with eip155 namespace.
• buildDidPkhFromCaip10(caip10: Caip10): Did — Build a did:pkh from a CAIP-10 string (e.g., "eip155:1:0x..." → "did:pkh:eip155:1:0x..."). Throws INVALID_CAIP.

DID Parsers

• getChainIdFromDidPkh(did: Did): string — Extract the chain ID from a did:pkh DID. Returns null if not a valid did:pkh. Returns the CAIP chain reference as a string; parse to number only for EVM (eip155) contexts.

  const chainRef = getChainIdFromDidPkh(did);
  const chainId = Number(chainRef); // EVM-only

• getAddressFromDidPkh(did: Did): string — Extract the address from a did:pkh DID. Returns null if not a valid did:pkh.

• getNamespaceFromDidPkh(did: Did): string — Extract the namespace (e.g., "eip155") from a did:pkh DID. Returns null if not a valid did:pkh.

• isEvmDidPkh(did: Did): boolean — Check if a did:pkh DID uses the eip155 (EVM) namespace.

• getDomainFromDidWeb(did: Did): string — Extract the domain from a did:web DID (e.g., "did:web:example.com/path" → "example.com"). Returns null if not a valid did:web.

• extractAddressFromDid(identifier: string): string — Extract an Ethereum address from a DID, CAIP-10 string, or raw address. Handles did:pkh, CAIP-10, and plain 0x addresses.

CAIP Utilities

CAIP-10 identifies a blockchain account as namespace:reference:address (e.g., eip155:1:0x...). CAIP-2 identifies a chain as namespace:reference (e.g., eip155:1).

• parseCaip10(input: string): { namespace: string; reference: string; address: string } — Parse a CAIP-10 string into its three components. Throws INVALID_CAIP if the format is invalid.
• buildCaip10(namespace: string, reference: string, address: string): Caip10 — Build a CAIP-10 string from components.
• normalizeCaip10(input: string): Caip10 — Parse, validate, and normalize a CAIP-10 string. Lowercases the address for EVM namespaces. Throws INVALID_CAIP.
• buildCaip2(namespace: string, reference: string): string — Build a CAIP-2 chain identifier string.
• parseCaip2(caip2: string): { namespace: string; reference: string } — Parse a CAIP-2 string into namespace and reference. Throws INVALID_CAIP.

DID URL Parsing

DID URLs are DIDs with a fragment (e.g., did:web:api.example.com#key-1). They are mutable key references — see Definitions: DID URL vs Controller DID.

parseDidUrl(input)

type ParsedDidUrl = {
  didUrl: string;
  did: string;
  fragment: string;
};
function parseDidUrl(input: string): ParsedDidUrl;

• Purpose: Parse a DID URL into its components.
• Example: did:web:api.example.com#key-1 → { didUrl: "did:web:api.example.com#key-1", did: "did:web:api.example.com", fragment: "key-1" }
• Throws: INVALID_DID_URL for malformed input or empty fragments.

isDidUrl(input)

function isDidUrl(input: string): boolean;

• Purpose: Returns true if the string is a DID URL (has a # fragment with a valid base DID).

assertBareDid(input)

function assertBareDid(input: string): void;

• Purpose: Throws if the input is a DID URL. Use in functions that expect a bare subject DID and must reject DID URLs.
• Throws: INVALID_DID_URL

JWK Helpers

Functions for working with JSON Web Keys (JWKs) and did:jwk DIDs. Used for non-EVM controller identities.

validatePublicJwk(jwk)

type JwkValidationResult = {
  valid: boolean;
  reason?: string;
};
function validatePublicJwk(jwk: unknown): JwkValidationResult;

• Purpose: Validate that a JWK is a well-formed public key.
• Checks kty (EC, OKP, RSA), required fields per key type, and rejects private key material (d, p, q, etc.).

jwkToDidJwk(jwk)

function jwkToDidJwk(jwk: unknown): string;

• Purpose: Convert a public JWK to a did:jwk DID.
• Uses deterministic (sorted-key) JSON + base64url encoding.
• Rejects private key material.
• Throws: INVALID_INPUT

didJwkToJwk(didJwk)

type PublicJwk = Record<string, unknown>;
function didJwkToJwk(didJwk: string): PublicJwk;

• Purpose: Convert a did:jwk DID back to a public JWK object.
• Validates the result.
• Throws: INVALID_DID

publicJwkEquals(a, b)

function publicJwkEquals(a: unknown, b: unknown): boolean;

• Purpose: Compare two public JWKs for equality.
• Ignores property order and metadata fields (kid, use, alg, key_ops, ext).
• Throws if either contains private key material.

computeJwkThumbprint(jwk, algorithm?)

function computeJwkThumbprint(
  jwk: unknown,
  algorithm?: "sha256" | "sha384" | "sha512"
): Promise<string>;

• Purpose: Compute an RFC 7638 JWK Thumbprint.
• Returns: base64url-encoded hash.
• Default algorithm: "sha256".

formatJktValue(jwk)

function formatJktValue(jwk: unknown): Promise<string>;

• Purpose: Returns jkt=S256:<thumbprint> format for DNS TXT records.

DID URL Key Resolution

Resolve DID URLs to their underlying public key material and derive durable controller DIDs.

resolveDidUrlToPublicKey(didUrl, options?)

type ResolvedPublicKey = {
  didUrl: string;
  did: string;
  fragment: string;
  publicKeyJwk: Record<string, unknown>;
  verificationMethodId: string;
};
function resolveDidUrlToPublicKey(
  didUrl: string,
  options?: { fetchDidDocument?: (domain: string) => Promise<Record<string, unknown>> }
): Promise<ResolvedPublicKey>;

• Purpose: Resolve a DID URL (e.g., did:web:api.example.com#key-1) to public key material.
• Fetches the DID document, finds the matching verification method, extracts and validates publicKeyJwk.
• Currently supports did:web.
• Throws: INVALID_DID_URL, NETWORK_ERROR

resolveDidUrlToControllerDid(didUrl, options?)

type ResolvedControllerDid = {
  didUrl: string;
  did: string;
  fragment: string;
  publicKeyJwk: Record<string, unknown>;
  verificationMethodId: string;
  controllerDid: string;
};
function resolveDidUrlToControllerDid(
  didUrl: string,
  options?: { fetchDidDocument?: (domain: string) => Promise<Record<string, unknown>> }
): Promise<ResolvedControllerDid>;

• Purpose: Wraps resolveDidUrlToPublicKey and derives a durable did:jwk controller DID from the resolved key.
• The controllerDid is what callers should pass to getControllerAuthorization. DID URLs are mutable key references — the derived did:jwk is the immutable controller identity.
• Throws: INVALID_DID_URL, NETWORK_ERROR

Controller ID Comparison

Functions for comparing controller DIDs across different formats and chains.

isSameControllerId(a, b)

function isSameControllerId(a: string, b: string): boolean;

• Purpose: Check if two controller DIDs refer to the same entity.
• Three matching strategies:
  1. Exact normalized DID string match
  2. EVM address match (chain-agnostic) — did:pkh:eip155:1:0xABC matches did:pkh:eip155:137:0xABC
  3. JWK material match — two did:jwk with the same key material but different encodings

extractControllerEvmAddress(controllerDid)

function extractControllerEvmAddress(controllerDid: string): string | null;

• Purpose: Extract the EVM address from a did:pkh:eip155:* DID.
• Returns null for non-EVM controllers (did:jwk, non-eip155 did:pkh, etc.).

Authorization Metadata

extractAuthorizationMetadata(result)

type JwsVerificationResult = {
  publicKeyDid: string;
  resourceUrl?: string;
  issuedAt?: number;
  kid?: string;
  publicKeyJwk?: Record<string, unknown>;
};

type AuthorizationMetadata = {
  controllerDid: string;
  subjectDid: string;
  resourceUrl: string;
  issuedAt: number;
  kid: string;
  publicKeyJwk: Record<string, unknown>;
};

function extractAuthorizationMetadata(result: JwsVerificationResult): AuthorizationMetadata;

• Purpose: Extract the metadata needed for a getControllerAuthorization call from a JWS verification result.
• Derives subjectDid from resourceUrl (assumes did:web for HTTPS URLs).
• Returns { controllerDid, subjectDid, resourceUrl, issuedAt, kid, publicKeyJwk }.

Data Utilities

These functions handle JSON canonicalization (JCS / RFC 8785). They are used in proof seed construction (constructSeed in the reputation module).

• canonicalizeJson(obj: unknown): string — JCS canonicalize any JSON-serializable object.
• canonicalizeForHash(obj: unknown): { jcsJson: string; hash: Hex } — Canonicalize and return both the JCS string and its keccak256 hash.