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  "title" : "Combining parameters to generate a signature for SKAdNetwork 1"
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# Combining parameters to generate a signature for SKAdNetwork 1

Generate signatures for apps compiled with earlier SDKs.

## Discussion

Generate a signature using the parameters for version 1.0 if you compile your app with an iOS SDK version from 11.3 through 13.7.

To generate the signature, first combine the values of [Ad network install-validation keys](/documentation/StoreKit/ad-network-install-validation-keys) for the version 1.0.

The parameters required for a version 1.0 signature are:

- [`SKStoreProductParameterAdNetworkIdentifier`](/documentation/StoreKit/SKStoreProductParameterAdNetworkIdentifier): Your ad network identifier that you registered with Apple. Shown as `ad-network-id` in [Combine the parameters for version 1.0](/documentation/StoreKit/combining-parameters-to-generate-a-signature-for-skadnetwork-1#Combine-the-parameters-for-version-10).
- [`SKStoreProductParameterAdNetworkCampaignIdentifier`](/documentation/StoreKit/SKStoreProductParameterAdNetworkCampaignIdentifier): A campaign number you provide. Shown as `campaign-id` in [Combine the parameters for version 1.0](/documentation/StoreKit/combining-parameters-to-generate-a-signature-for-skadnetwork-1#Combine-the-parameters-for-version-10).
- [`SKStoreProductParameterITunesItemIdentifier`](/documentation/StoreKit/SKStoreProductParameterITunesItemIdentifier): The App Store ID of the product to advertise. Shown as `itunes-item-id` in [Combine the parameters for version 1.0](/documentation/StoreKit/combining-parameters-to-generate-a-signature-for-skadnetwork-1#Combine-the-parameters-for-version-10).
- [`SKStoreProductParameterAdNetworkNonce`](/documentation/StoreKit/SKStoreProductParameterAdNetworkNonce): A unique `UUID` value that you provide for each ad impression. You must lowercase the string representation of the nonce in the signature. Shown as `nonce` in [Combine the parameters for version 1.0](/documentation/StoreKit/combining-parameters-to-generate-a-signature-for-skadnetwork-1#Combine-the-parameters-for-version-10).
- [`SKStoreProductParameterAdNetworkTimestamp`](/documentation/StoreKit/SKStoreProductParameterAdNetworkTimestamp): A timestamp you generate near the time of the ad impression. Shown as `timestamp` in [Combine the parameters for version 1.0](/documentation/StoreKit/combining-parameters-to-generate-a-signature-for-skadnetwork-1#Combine-the-parameters-for-version-10).

### Combine the parameters for version 1.0

Create the UTF-8 string for version 1.0 if you compile your app with an SDK prior to iOS 14.

> Important:
> You must use lowercase for the string representation of the nonce: ``doc://com.apple.storekit/documentation/StoreKit/SKStoreProductParameterAdNetworkNonce``.

Combine the values into a UTF-8 string with an invisible separator (`‘\u2063’`) between them, in the exact order shown:

```javascript
ad-network-id + '\u2063' + campaign-id + '\u2063' + itunes-item-id + '\u2063' + nonce + '\u2063' + timestamp
```

Next, follow the instructions to sign the combined string, encode the signature, and use the generated signature string as described in [Generating the signature to validate StoreKit-rendered ads](/documentation/StoreKit/generating-the-signature-to-validate-storekit-rendered-ads).

---

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