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# kSecAttrAuthenticationType

A key whose value indicates the item’s authentication scheme.

```
let kSecAttrAuthenticationType: CFString
```

## Discussion

The corresponding value is of type <doc://com.apple.documentation/documentation/CoreFoundation/CFString> and denotes the authentication scheme for this item (see [Authentication Type Values](/documentation/Security/item-attribute-keys-and-values#Authentication-Type-Values)).

> Note:
> For compatibility with earlier Keychain APIs, functions in <doc://com.apple.security/documentation/Security/keychain-services> accept a <doc://com.apple.documentation/documentation/CoreFoundation/CFNumber> for the authentication scheme. The number is a 32-bit integer that encodes the authentication scheme as a `FourCharCode`. In your code, use a <doc://com.apple.documentation/documentation/CoreFoundation/CFString> with one of the values from <doc://com.apple.security/documentation/Security/item-attribute-keys-and-values#Authentication-Type-Values> instead of a number.

---

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