# How to use a link signature key

Copy for LLM[View as Markdown](/articles/managing-your-account-and-domains/manage-your-domain/how-to-manage-link-signature-keys.md)

With the help of our **link signature key** feature, you can sign links using a domain-specific key and enforce an organization-wide login policy.

When this option is enabled, every redirect on a specific domain includes a signature generated using HMAC-SHA3-512. The signature is composed of the following parameters:

* **si\_sig** - the cryptographic signature itself. If an unauthorized user modifies the link parameters, the signature becomes invalid and user's access is blocked

* **si\_exp** - the expiration timestamp. This dictates the exact date and time when the link will automatically stop working. It prevents long-term exposure or reuse of the link. The validity period is 10 minutes

* **si\_alg** - the cryptographic algorithm used to generate the signature

Your destination server can verify the signature to confirm that the request came from **Short.io** and the destination URL has not been changed.

## Adding a signature key[​](#adding-a-signature-key "Direct link to Adding a signature key")

By default, link signing is disabled. To generate a signature key, follow these steps:

1. [**Select the domain**](/articles/managing-your-account-and-domains/manage-your-domain/how-to-switch-between-domains.md) where you want to add signature key.

2. From the left side menu, navigate to **Dashboard -> Domain settings** and click **Signature key**:

   ![](/assets/images/sshot_link_signature_key-3efb8a9a32684dd05bf600630b7c715c.png)

3. Click **Generate signature key**:

   ![](/assets/images/sshot_link_signature_key_add-77aa23bf2f3a09934464ff860459239d.png)

4. When the next dialog appears, copy  the unique signature key:

   ![](/assets/images/dlg_signature_key_generate-bb858a2bf444155588c20a510d9ee332.png)

   Important note

   Copy and safely store this key. For security reasons, it will not be shown again. You can generate a new key at any time.

5. Click **Done**.

   The key will be added to the domain.

   ![](/assets/images/sshot_link_signature_key_added-c13ba1ed7f9e205e009b76c7a53bc053.png)

## Regenerating signature key[​](#regenerating-signature-key "Direct link to Regenerating signature key")

If you forget your signature key or need to replace it for security reasons, you can regenerate it as follows:

1. From **Domain settings -> Signature key**, click **Regenerate key**:

   ![](/assets/images/sshot_link_signature_key_regenerate-587f09b1a1e3f92993ec7b8b49043c8e.png)

2. When the **Regenerate signing key?** dialog appears, click **Continue**:

   ![](/assets/images/dlg_signature_key_regenerate-5d9e37baa894e2d49869e3e945dc196d.png)

   The new key will be displayed:

   ![](/assets/images/dlg_signature_key_regenerated_done-ecd8600b6894df30ce764d02353e69bb.png)

   Important note

   Copy and safely store this key. For security reasons, it will not be shown again. You can generate a new key at any time.

3. Click **Done**.

   The new key will be added to the domain.

   ![](/assets/images/sshot_signature_key_new_regenerated-ba72e75f1398ddd4667bd7af7ff87666.png)

## Disabling signature key[​](#disabling-signature-key "Direct link to Disabling signature key")

If you no longer want to apply signature key to a given domain, disable it as follows:

1. From **Domain settings -> Signature key**, click **Disable signing**:

   ![](/assets/images/sshot_link_signature_key_disable-b2928d1d5e2a0ccc64937ba0cdb0ef1a.png)

2. When the **Disable link signing?** dialog appears, click **Continue**:

   ![](/assets/images/dlg_signature_key_disable-b2f7d8c7ef4a4f361bd0c30fe7b19882.png)

   The key will be removed and no longer valid.