NewApp creates a new Keychain application, using the given configuration.

App is the Keychain application.

Config is the configuration for the Keychain.

KeyResponseWriter is the interface for writing responses to key requests.

SignaResponseWriter is the interface for writing responses to sign requests.

KeyRequest is a key request.

KeyRequestHandler is a function that handles key requests.

SignRequest is a sign request.

SignRequestHandler is a function that handles sign requests.