---
title: "init(first:second:)"
framework: authenticationservices
role: symbol
role_heading: Initializer
path: "authenticationservices/asauthorizationpublickeycredentialprfassertionoutput-swift.struct/init(first:second:)"
---

# init(first:second:)

Initializes an assertion output structure with one or two keys.

## Declaration

```swift
init(first: SymmetricKey, second: SymmetricKey?)
```

## Parameters

- `first`: A symmetric key that’s unique to the passkey and derives from the first input.
- `second`: A second symmetric key that’s unique to the passkey, and derives from the second input, if specified.