> ## 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>

## `areIdentitiesHashed` & `hashIdentities`

These two configuration options work together to control how the Zeotap iOS 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/ios/api-reference/set-user-identities#pii-identifier-key-reference)
</Note>

## Options Definitions

* **`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`).

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

## Default Behavior

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

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

This means by default, the SDK sends raw PII values without any client-side hashing.

## Combined usage

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

### Scenario 1: Sending Raw Identifiers (Default)

```swift theme={null}
var collectOptions = CollectOption()
    .writeKey(value: "YOUR_WRITE_KEY")
    .areIdentitiesHashed(false)   // or omit (default)
    .hashIdentities(false)        // or omit (default)
    .build()

Collect.initialize(option: collectOptions)

// Later in your code
Collect.getInstance()?.setUserIdentities([
    "email": "user@example.com",     // Raw email
    "cellno": "+1234567890"          // Raw phone number
])
```

### Scenario 2: Sending Pre-Hashed Identifiers

```swift theme={null}
var collectOptions = CollectOption()
    .writeKey(value: "YOUR_WRITE_KEY")
    .areIdentitiesHashed(true)
    .hashIdentities(false)
    .build()

Collect.initialize(option: collectOptions)

// Later in your code - using hashed keys
Collect.getInstance()?.setUserIdentities([
    "email_sha256_lowercase": "5d41402abc4b2a76b9719d911017c592",  // Pre-hashed email
    "cellno_sha256": "e3b0c44298fc1c149afbf4c8996fb924"             // Pre-hashed phone
])
```

### Scenario 3: SDK Performs Hashing

```swift theme={null}
var collectOptions = CollectOption()
    .writeKey(value: "YOUR_WRITE_KEY")
    .areIdentitiesHashed(false)
    .hashIdentities(true)
    .build()

Collect.initialize(option: collectOptions)

// Later in your code
Collect.getInstance()?.setUserIdentities([
    "email": "user@example.com",     // Raw email - SDK will hash
    "cellno": "+1234567890"          // Raw phone - SDK will hash
])
```

<Tip>
  **Recommendation**

  It is **highly recommended** to explicitly set both `areIdentitiesHashed` and `hashIdentities` in your `CollectOption` configuration to clearly document your intended hashing strategy and avoid potential confusion.
</Tip>

<Warning>
  **Invalid Configuration**

  Setting both `areIdentitiesHashed: true` and `hashIdentities: 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>

## Hashing Algorithm

When `hashIdentities` is set to `true`, the iOS SDK uses SHA-256 hashing algorithm to hash PII values before transmission.

## Related Topics

* [`setUserIdentities`](/articles/sdks/ios/api-reference/set-user-identities) API Reference
* [Configuration Overview](/articles/sdks/ios/configurations/overview) for all available SDK options