Identity & Attestations

Every Ankara template can be gated by an identity verifier: on mint and on every transfer, the token calls is_verified(account) on whatever contract is set as its identity_verifier. Two contracts implement that interface on Stellar:

Contract	Use it when
`whitelist-verifier`	You want a simple admin-managed allow-list (with optional expiry). Good default for pilots and dev.
`attestation-registry`	You want trusted third parties (a KYC provider, a land registry, a warehouse) to record facts that anyone can check later — KYC is one claim type among many.

Both are Stellar-only and have no EVM counterpart beyond WhitelistVerifier.sol.

whitelist-verifier

Soroban port of WhitelistVerifier.sol — admin-controlled allow-list implementing IdentityVerifierInterface.

Function	Access	Notes
`initialize(admin)`	once
`verify(account)`	admin	never expires
`verify_until(account, expires_at)`	admin	unix seconds; `is_verified` turns `false` after it
`revoke(account)`	admin
`batch_verify(accounts)` / `batch_revoke(accounts)`	admin	max 50 per call
`transfer_admin(new_admin)`	admin	e.g. hand over to a multisig
`is_verified(account)`	anyone	the verifier interface
`get_record(account)`	anyone	`{ verified_at, expires_at }` or none

Deploy

cd packages/contracts-stellar
npm run build
VERIFIER=$(stellar contract deploy --wasm target/wasm32v1-none/release/whitelist_verifier.wasm --source deployer --network testnet)
stellar contract invoke --id $VERIFIER --source deployer --network testnet -- initialize --admin <ADMIN_ADDRESS>

Then point a token at it (at deploy time via verifierAddress, or later):

import { AssetRegistry, WhitelistVerifier } from "@ankarachain/sdk";

const verifier = new WhitelistVerifier(stellarAdapter, VERIFIER);
await verifier.batchVerify(["GALICE...", "GBOB..."]);
await verifier.verifyUntil("GCAROL...", BigInt(Math.floor(Date.now() / 1000) + 365 * 86400));

const registry = new AssetRegistry(stellarAdapter, tokenAddress, "farmland");
await registry.setIdentityVerifier(VERIFIER);

attestation-registry

A generic “someone trusted records a fact, anyone can verify it later” primitive. An allow-listed attestor records a typed claim about a subject:

Subject — Account(address) or Asset(asset_id) (the same 32-byte asset_id every template is initialized with; the SDK hashes your asset ID string the same way TokenFactory does).
Claim type — a short Symbol you choose, e.g. KYC, TITLE, DELIVERY, CREDIT.
value (i128) — numeric payload: KYC tier, credit score, quantity delivered, 1/0.
data (String) — anything else: document hash, registry reference, URI, small JSON.
expires_at — unix seconds, or 0 for never.

History is append-only: revoking a claim marks it revoked but keeps it readable.

Use case	subject	claim_type	value / data
KYC status	`Account`	`KYC`	tier (`> 0` = verified)
Land-title chain of custody	`Asset`	`TITLE`	— / new owner + deed hash
Delivery / harvest confirmation	`Asset`	`DELIVERY`	quantity / receipt hash
Credit / reputation signal	`Account`	`CREDIT`	score / model reference

Function	Access
`add_attestor(a)` / `remove_attestor(a)` / `set_verifier_claim_type(t)`	admin
`attest(attestor, subject, claim_type, value, data, expires_at) -> id`	attestor
`revoke(caller, id)`	the claim’s attestor, or admin
`get_attestation(id)`, `latest(subject, type)`, `has_valid_claim(subject, type)`	anyone
`history(subject, type, start, limit)` (max 50), `claim_count(subject, type)`	anyone
`is_verified(account)`	anyone — verifier interface

As an identity verifier

The registry implements is_verified too: an account is verified when its latest valid claim of the verifier claim type (default KYC) has value > 0. So a KYC provider can be made an attestor and every template pointed straight at the registry.

import { AttestationRegistry } from "@ankarachain/sdk";

const registry = new AttestationRegistry(adminAdapter, REGISTRY);
await registry.addAttestor("GKYCPROVIDER...");

// As the KYC provider:
const asProvider = new AttestationRegistry(providerAdapter, REGISTRY);
await asProvider.attest({ subject: { kind: "account", address: "GALICE..." }, claimType: "KYC", value: 2n });

// Land-title provenance for a deployed farmland token:
await asProvider.attest({
  subject: { kind: "asset", assetId: "FARM-OYO-2024-001" },
  claimType: "TITLE",
  value: 0n,
  data: JSON.stringify({ owner: "GBUYER...", deed: "0xabc..." }),
});
const chain = await registry.history({ kind: "asset", assetId: "FARM-OYO-2024-001" }, "TITLE");

Deploy

REGISTRY=$(stellar contract deploy --wasm target/wasm32v1-none/release/attestation_registry.wasm --source deployer --network testnet)
stellar contract invoke --id $REGISTRY --source deployer --network testnet -- initialize --admin <ADMIN_ADDRESS>

SDK

Types & Config

Contracts

Stellar modules

Identity & Attestations

whitelist-verifier

Deploy

attestation-registry

As an identity verifier

Deploy

​whitelist-verifier

​Deploy

​attestation-registry

​As an identity verifier

​Deploy

whitelist-verifier

Deploy

attestation-registry

As an identity verifier

Deploy