/ref-OpenHealthCardKit

Controlling/Use-case framework for accessing smart cards of the telematic infrastructure. API Documentation: https://gematik.github.io/ref-OpenHealthCardKit

Primary LanguageSwiftOtherNOASSERTION

OpenHealthCardKit

Controlling/Use-case framework for accessing smart cards of the telematic infrastructure.

Introduction

The OpenHealthCardKit module is intended for reference purposes when implementing a system that performs the communication between an iOS based mobile device and a German Health Card (elektronische Gesundheitskarte) using an NFC, Blue Tooth oder USB interface.

This document describes the functionalitiy and structure of OpenHealthCardKit.

API Documentation

Generated API docs are available at https://gematik.github.io/ref-OpenHealthCardKit.

License

Licensed under the Apache License, Version 2.0.

Getting Started

OpenHealthCardKit requires Swift 5.1.

Setup for integration

  • Carthage: Put this in your Cartfile:

    github "gematik/ref-openHealthCardKit" ~> 1.0
    

Setup for development

You will need Bundler, XcodeGen and fastlane to conveniently use the established development environment.

  1. Update ruby gems necessary for build commands

    $ bundle install --path vendor/gems
    
  2. Checkout (and build) dependencies and generate the xcodeproject

    $ bundle exec fastlane setup
    
  3. Build the project

    $ bundle exec fastlane build_all [build_mac, build_ios]
    

Overview

OpenHealthCardKit bundles submodules that provide the functionality necessary for accessing and interacting with German Health Cards via a mobile iOS device.

OpenHealthCardKit consists of the submodules

  • CardReaderProviderApi

  • HealthCardAccess

  • HealthCardControl

  • NFCCardReaderProvider

As a reference for each submodule see also the IntegrationTests. Also see a Demo App on GitHub using this framework.

CardReaderProviderApi

(Smart)CardReader protocols for interacting with HealthCardAccess.

HealthCardAccess

This library contains the classes for cards, commands, card file systems and error handling.

HealthCardAccess API

The HealthCardAccessKit API Structure contains the HealthCard class representing all supported card types, the Commands and Responses groups with all supported commands and responses for health cards, the CardObjects group with the possible objects on a health cards and the Operation group for cascading and executing commands on health cards.

Health Cards

The class HealthCard represents the potential types of health cards by storing a HealthCardStatus property which in case of being valid by itself stores a HealthCardPropertyType which at the time of writing is represented by either one of the following

  • egk ("elektronische Gesundheitskarte")

  • hba ("Heilberufeausweis")

  • smcb ("Security Module Card Typ B").

The HealthCardPropertyType by itself stores the CardGeneration (G1, G1P, G2, G2.1) as well.

Furthermore the HealthCard object contains the physical card from a card reader and the current card channel.

Commands

The Commands groups contains all available HealthCardCommand objects for health cards through the HealthCardCommandBuilder.

Code Samples

Create a command

The design of this API follows the command design pattern leveraging Swift’s Combine Framework. The command objects are designed to fulfil the use-cases described in the Gematik COS specification. After creating a command object resp. sequence you can execute it on a Healthcard with the help of publisher(for:). More information on how to configure the commands can also be found in the Gematik COS specification.

Following example shall send a SELECT and a READ command to a smart card in order to select and read the certificate stored in the file EF.C.CH.AUT.R2048 in the application ESIGN.

First we want to to create a SelectCommand object passing a ApplicationIdentifier. We use one of the predefined helper functions by using HealthCardCommand.Select.

One could also use the HealthCardCommandBuilder to construct a customized HealthCardCommand by setting the APDU-bytes manually.

let eSign = EgkFileSystem.DF.ESIGN
let selectEsignCommand = HealthCardCommand.Select.selectFile(with: eSign.aid)
Setting an execution target

We execute the created command CardType instance which has been typically provided by a CardReaderType.

In the next example we use a HealthCard object representing an eGK (elektronische Gesundheitskarte) as one kind of a HealthCardType implementing the CardType protocol.

// initialize your CardReaderType instance
let cardReader: CardReaderType = CardSimulationTerminalTestCase.reader
let card = try cardReader.connect([:])!
let healthCardStatus = HealthCardStatus.valid(cardType: .egk(generation: .g2))
let eGk = try HealthCard(card: card, status: healthCardStatus)
let publisher: AnyPublisher<HealthCardResponseType, Error> = selectEsignCommand.publisher(for: eGk)

A created command can be lifted to the Combine framework with publisher(for:writetimeout:readtimeout). The result of the command execution can be validated against an expected ResponseStatus, e.g. SUCCESS (0x9000).

let checkResponse = publisher.tryMap { healthCardResponse -> HealthCardResponseType in
    guard healthCardResponse.responseStatus == ResponseStatus.success else {
        throw HealthCard.Error.operational // throw a meaningful Error
    }
    return healthCardResponse
}
Create a Command Sequence

It is possible to chain further commands via the flatMap operator for subsequent execution: First create a command and lift it onto a Combine monad, then create a publisher using the flatMap operator, e.g.

Just(AnyHealthCardCommand.build())
    .flatMap { command in command.pusblisher(for: card) }

Eventually use eraseToAnyPublisher().

let readCertificate = checkResponse
        .tryMap { _ -> HealthCardCommandType in
            let sfi = EgkFileSystem.EF.esignCChAutR2048.sfid!
            return try HealthCardCommand.Read.readFileCommand(with: sfi, ne: 0x076C - 1)
        }
        .flatMap { command in
            command.publisher(for: eGk)
        }
        .eraseToAnyPublisher()
Process Execution result

When the whole command chain is set up we have to subscribe to it. We really only will receive one value before completion, so something as simple as this sink() convenience publisher is useful.

readCertificate
        .sink(
        receiveCompletion: { completion in
            switch completion {
            case .finished:
                DLog("Completed")
            case .failure(let error):
                DLog("Error: \(error)")
            }
        },
        receiveValue: { healthCardResponse in
            DLog("Got a certifcate")
            let certificate = healthCardResponse.data!
            // proceed with certificate data here
            // use swiftUI to a show success message on screen etc.
        }
)

HealthCardControl

This library can be used to realize use cases for interacting with a German Health Card (eGk, elektronische Gesundheitskarte) via a mobile device.

Typically you would use this library as the high level API gateway for your mobile application to send predefined command chains to the Health Card and interpret the responses.

For more info, please find the low level part HealthCardAccess. and a Demo App on GitHub.

See the Gematik GitHub IO page for a more general overview.

Code Samples

Take the necessary preparatory steps for signing a challenge on the Health Card, then sign it.

expect {
    let challenge = Data([0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8])
    let format2Pin = try Format2Pin(pincode: "123456")
    return try Self.healthCard.verify(pin: format2Pin, type: EgkFileSystem.Pin.mrpinHome)
            .flatMap { _ in
                Self.healthCard.sign(challenge: challenge)
            }
            .eraseToAnyPublisher()
            .test()
            .responseStatus
} == ResponseStatus.success

Encapsulate the PACE protocol steps for establishing a secure channel with the Health Card and expose only a simple API call .

try KeyAgreement.Algorithm.idPaceEcdhGmAesCbcCmac128.negotiateSessionKey(
                card: CardSimulationTerminalTestCase.healthCard,
                can: can,
                writeTimeout: 0,
                readTimeout: 10)

See the integration tests IntegrationTests/HealthCardControl/ for more already implemented use cases.

NFCCardReaderProvider

A CardReaderProvider implementation that handles the communication with the Apple iPhone NFC interface.