> ## Documentation Index
> Fetch the complete documentation index at: https://turnkey-0e7c1f5b-bc-add-sdk-typedoc.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# VerifyStampSignature

# Function: verifyStampSignature()

> **verifyStampSignature**(`publicKey`, `signature`, `signedData`): `Promise`\<`boolean`>

Defined in: [turnkey.ts:193](https://github.com/tkhq/sdk/blob/ee72856c3f450731d7501ab05001215768b71500/packages/crypto/src/turnkey.ts#L193)

Verifies a signature from a Turnkey stamp using ECDSA and SHA-256.

## Parameters

### publicKey

`string`

The public key of the authenticator (e.g. WebAuthn or P256 API key).

### signature

`string`

The ECDSA signature in DER format.

### signedData

`string`

The data that was signed (e.g. JSON-stringified Turnkey request body).

## Returns

`Promise`\<`boolean`>

* Returns true if the signature is valid, otherwise throws an error.

## Example

```ts theme={"system"}
const stampedRequest = await turnkeyClient.stampGetWhoami(...);
const decodedStampContents = atob(stampedRequest.stamp.stampHeaderValue);
const parsedStampContents = JSON.parse(decodedStampContents);
const signature = parsedStampContents.signature;

await verifyStampSignature(publicKey, signature, stampedRequest.body)
```