> For the complete documentation index, see [llms.txt](https://docs.licensespring.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.licensespring.com/license-api/license-api-authorization/response-signature-v2.md).

# Response Signature v2

### Overview

Response objects from License API endpoints contain an HTTP header `LicenseSignature` which is an HMAC-SHA256 signature used to verify the integrity and authenticity of the response. This is not the same as the `license_signature` in certain response objects (see [**Response Signature**](/license-api/license-api-authorization/response-signature.md) for that property).

The `LicenseSignature` header signs the entire response object using our private key, which enables you to use our public key to verify the signature.

### Verifying Response Signature v2

You can use the server's public key to verify the `LicenseSignature` header. By validating the signature, you ensure the response originates from LicenseSpring's trusted servers.

Download the server public key from below to implement signature verification using the example provided:

{% file src="/files/xJMFdFtJYBbfnD7KR8VS" %}

### Code Sample

{% code title="verify-response-signature.js" %}

```javascript
import crypto from 'node:crypto'
import dayjs from 'dayjs'
import utc from 'dayjs/plugin/utc.js'

dayjs.extend(utc)

// Header and response received from our servers:
const responseLicenseSignatureHeader = '...';
const responseBody = {
  // ... response object from LicenseSpring's server ...
};

/* 
  NOTE: specifically for the Activate License Offline endpoint, existing
  signatures in the response body need to be removed before calculating
  the v2 signature, like this:
  
  delete responseBody.license_signature;
  delete responseBody.license_signature_v2;
*/

const verifier = crypto.createVerify('RSA-SHA256');
verifier.update(JSON.stringify(response));
const result = verifier.verify(publicKey, responseLicenseSignatureHeader, 'base64');

console.log(result); // will be "true" if signature is valid
```

{% endcode %}


---

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