---
title: "init(_:)"
framework: wifiaware
role: symbol
role_heading: Initializer
path: "wifiaware/washaredsecret/protocolname/init(_:)-7marr"
---

# init(_:)

Creates a custom protocol name using the provided unique string.

## Declaration

```swift
init?(_ string: String)
```

## Parameters

- `string`: The string to use as the underlying protocol name, which must be equal to or greater than three characters long. The framework converts the string to UTF-8 prior to hashing in the derivation.

## Return Value

Return Value A new WASharedSecret.ProtocolName, or nil if the provided string is too short.

## Discussion

Discussion Custom protocols need to specify a string that identifies the protocol that uses the shared secret. The string must be representable as UTF-8, and normalize to the same value when represented as bytes. A best practice is to use ASCII-compatible values to avoid normalization issues. Set the same value on the local and remote devices in order to generate the same shared secret.