---
title: "init(keyType:cipherSuite:version:key:supportedTransports:identifier:)"
framework: accessorytransportextension
role: symbol
role_heading: Initializer
path: "accessorytransportextension/securitymessage/init(keytype:ciphersuite:version:key:supportedtransports:identifier:)"
---

# init(keyType:cipherSuite:version:key:supportedTransports:identifier:)

Initializes a security message with key material and metadata.

## Declaration

```swift
init(keyType: SecurityMessage.KeyType, cipherSuite: SecurityMessage.CipherSuite, version: SecurityMessage.CipherSuite.Version, key: Data, supportedTransports: [AccessoryTransport] = [.bluetooth], identifier: String? = nil)
```

## Parameters

- `keyType`: The type of key carried by this message.
- `cipherSuite`: The cryptographic cipher suite to use for key exchange.
- `version`: The cipher suite protocol version.
- `key`: The key data to send.
- `supportedTransports`: The transports the accessory supports for sending sensitive information. The default is Bluetooth only.
- `identifier`: An optional Bluetooth identifier for deriving HPKE keys.

## Discussion

Discussion When initiating key exchange from your accessory, create a message with SecurityMessage.KeyType.publicKey and your accessory’s public key. The system responds with a message containing SecurityMessage.KeyType.encapsulatedKey.