> ## Documentation Index
> Fetch the complete documentation index at: https://trust-link-tsn.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# resolveTIN — read a TIN account from Solana

> Reads a TIN account, decodes its identity route, and reports whether the stored record is ready for current TSN settlement use.

## What it does

`resolveTIN` reads the requested TIN from the configured Solana connection.
It first checks the current TIN registry PDA, then falls back to scanning the
program for the legacy account layout when no current registry exists. The
result includes the display name, account kind, route commitments, status, and
whether the stored encrypted material requires an upgrade.

## How the flow works

<Steps>
  <Step title="Caller invokes the function">
    The caller supplies a TIN, a Solana `Connection`, and optionally the TIN
    program ID. A lookup secret can be supplied for the private resolver path.
  </Step>

  <Step title="Validation">
    The SDK derives the current registry PDA and requests the account. If the
    account is absent, it searches the program for a matching legacy TIN
    account. If neither exists, it throws a not-found error.
  </Step>

  <Step title="Main work">
    The SDK decodes the account, checks the stored route and encrypted
    master-seed envelope, and maps the on-chain fields into a resolved identity
    object. A supplied `lookupSecret` selects the private resolution path.
  </Step>

  <Step title="Result">
    The promise resolves with the TIN, display name, authority account,
    account kind, readiness flags, and route commitments. No account is
    modified.
  </Step>
</Steps>

## Signature

```ts theme={null}
export async function resolveTIN(params: {
  tin: bigint | number | string;
  connection: Connection;
  programId?: PublicKey | string | null;
  lookupSecret?: Uint8Array | string;
  sensitiveAuthorizations?: Record<string, Uint8Array | string>;
}): Promise<TinResolvedIdentity>;
```

## Errors

| Error                                                | When it occurs                                                         |
| ---------------------------------------------------- | ---------------------------------------------------------------------- |
| `TIN <value> was not found in TIP program <program>` | Neither the current registry PDA nor a legacy account matches the TIN. |
| Resolver errors from the Solana connection           | The RPC request fails or returns malformed account data.               |

## Example

```ts theme={null}
import { Connection } from "@solana/web3.js";
import { resolveTIN } from "@trustlink/tsn-sdk";

const identity = await resolveTIN({
  tin: "1234567890",
  connection: new Connection("https://api.devnet.solana.com"),
});

console.log(identity.name, identity.accountKind, identity.upgradeRequired);
```

## Source

[tins.ts:1484](https://github.com/Trustlink-Labs/TSN-Protocol/blob/main/tsn-protocol/sdks/tsn-sdk/src/tins.ts#L1484)