> ## Documentation Index
> Fetch the complete documentation index at: https://docs.zeotap.com/llms.txt
> Use this file to discover all available pages before exploring further.

# PII Hashing Configuration

> Understand how to configure PII hashing behavior using hashIdentities and areIdentitiesHashed options.

<Warning>
  **Important:** Please ensure your CMP configuration includes new **Vendor ID 1469** for 1st Party data tracking. Additionally, include **Vendor ID 301** if cookie sync is enabled. [Learn more](/articles/sdks/web-js/configurations/consent-options#shouldcheckzeotapvendorconsent)
</Warning>

## `hashIdentities` & `areIdentitiesHashed`

These two configuration options work together to control how the Zeotap SDK handles Personal Identifiable Information (PII) like email addresses and phone numbers when you call the `setUserIdentities` function. Correctly configuring these options is crucial for ensuring data is processed according to your intended hashing strategy.

<Note>
  **PII**

  These configuration only affect PIIs sent using setUserIdentities function. Recognised PIIs are cellno, email, loginid. [Learn more about PIIs](/articles/sdks/web-js/api-reference/set-user-identities#pii-identifier-key-reference)
</Note>

## Options Definitions

* **`hashIdentities`**
  * **Type:** `Boolean`
  * **Default:** `true`
  * **Description:** Tells the SDK whether **it should perform** client-side hashing (SHA-256, MD5, SHA-1) on raw PII values (`email`, `cellno`, `loginid`) provided to `setUserIdentities` before sending the data to the Zeotap backend.

* **`areIdentitiesHashed`**
  * **Type:** `Boolean`
  * **Default:** `false`
  * **Description:** Tells the SDK whether the PII values you are **providing** in the `setUserIdentities` call are *already* hashed. If `true`, you must use the specific hashed keys (e.g., `email_sha256_lowercase`).

## Default Behavior

If you do **not** explicitly set `hashIdentities` or `areIdentitiesHashed` during `init`:

* `hashIdentities` defaults to `true`.
* `areIdentitiesHashed` defaults to `false`.

See all the cases and usage in [Choosing Your Hashing Strategy](/articles/sdks/web-js/api-reference/set-user-identities#choosing-your-hashing-strategy).

## Combined usage

| `hashIdentities` | `areIdentitiesHashed` | Resulting Scenario                                                                                                    |
| :--------------- | :-------------------- | :-------------------------------------------------------------------------------------------------------------------- |
| `false`          | `false`               | [**1: Sending Raw**](/articles/sdks/web-js/api-reference/set-user-identities#sending-raw-identifiers)                 |
| `false`          | `true`                | [**2: Sending Pre-Hashed**](/articles/sdks/web-js/api-reference/set-user-identities#sending-pre-hashed-identifiers)   |
| `true`           | `false`               | [**3: SDK Performs Hashing**](/articles/sdks/web-js/api-reference/set-user-identities#sdk-performs-hashing) (Default) |
| `true`           | `true`                | **Invalid**                                                                                                           |

<Tip>
  **Recommendation**

  While the defaults lead to [**Scenario 3: SDK Performs Hashing**](/articles/sdks/web-js/api-reference/set-user-identities#sdk-performs-hashing), it is **highly recommended** to explicitly set both `hashIdentities` and `areIdentitiesHashed` in your `init` configuration to clearly document your intended hashing strategy and avoid potential confusion.
</Tip>

<Warning>
  **Invalid Configuration**

  Setting both `hashIdentities: true` and `areIdentitiesHashed: true` simultaneously is an invalid configuration.

  This creates a conflict: the SDK is being told to hash data that is also being declared as already hashed. This can lead to incorrect, double-hashed data.

  **Do not use this combination.**
</Warning>

## Related Topics

* [`Track User Identities`](/articles/sdks/web-js/api-reference/set-user-identities) API Reference