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  "title" : "Combining parameters to generate signatures for SKAdNetwork 2.2 and 3"
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# Combining parameters to generate signatures for SKAdNetwork 2.2 and 3

Generate signatures to sign your ad with versions 2.2 and 3.

## Discussion

To generate the signature, combine the required values of [Ad network install-validation keys](/documentation/StoreKit/ad-network-install-validation-keys) for version 2, and include a `fidelity-type` value of `1` for StoreKit-rendered ads.

> Important:
> Lowercase the string representation of the nonce: ``doc://com.apple.storekit/documentation/StoreKit/SKStoreProductParameterAdNetworkNonce``. Failing to do so results in an invalid signature. Only ads with valid signatures can get ad attributions.

For versions 2.2 and 3, combine the values into a UTF-8 string with an invisible separator (`‘\u2063’`) between them, in the exact order the code below shows:

```javascript
//Parameter values combined, in order, for version 2.2 and 3.
version + '\u2063' + ad-network-id + '\u2063' + campaign-id + '\u2063' + itunes-item-id + '\u2063' + nonce + '\u2063' + source-app-id + '\u2063' + fidelity-type + '\u2063' + timestamp
```

---

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