NBT APDU Swift library

Swift library to communicate using APDUs with the OPTIGA™ Authenticate NBT

The NBT APDU Swift library allows the iOS application to send C-APDUs and receive R-APDUs from the OPTIGA™ Authenticate NBT. This library can be used with any communication channel, such as NFC and PCSC.

Features

• Supports personalization and operational commands of OPTIGA™ Authenticate NBT applet

• Configuration of OPTIGA™ Authenticate NBT via its configurator applet

• Extensible for any communication channel such as NFC and PCSC

Features not supported

• Pass-through APDUs

Usage

1. Include the following headers

   import Foundation
   import InfineonApdu
   import InfineonApduNbt
   import InfineonLogger
   

2. Create a logger

   Refer to hsw-logger-swift/README.md example section for creating a logger.

   //TODO: Implement example logger
   

   Initialize the created logger.

   //Initialize the Logger
   let exampleLogger : ExampleLogger = ExampleLogger()
   //Set the log level (The logger levels, in order of increasing verbosity, are: `none`, `error`, `warning`, `info`, `debug`, and `all`)
   exampleLogger.setLogLevel(loggerLevel: LoggerLevel.info)
   

3. Create a communication channel

   Refer to hsw-channel-swift/README.md example section for creating a communication channel interface.

   // Implement example communication channel interface(e.g PCSC, NFC)
   // Code placeholder
   

   Initialize the created communication channel.

   // Initialize the Channel interface
   let exampleChannel = ExampleChannel()
   // Initialize the APDU channel with communication channel and logger
   let apduChannel =  ApduChannel(channel : ctkChannel, logger: exampleLogger)
   

4. Initialize the command set

   // Create an instance of the NBT APDU command set
   let commandSet = try NbtCommandSet(channel: apduChannel)
   
   // Connect to the OPTIGA™ Authenticate NBT (It can return empty data)
   _ = try await apduChannel.connect(data: nil)
   

5. Communicate with the OPTIGA™ Authenticate NBT

   do {
   // Execute commands
   var apduResponse = try await commandSet.selectApplication()
   // Checks APDU Status word(SW) success, else throws an error
   _ = try apduResponse.checkOK() // Returns the Apdu response object
   _ = apduResponse.getSW() // Returns response status word
   //Log the Apdu response
   exampleLogger.info(header: "APDU response", data: apduResponse.getData())
   
   let ccFileId: UInt16 = 0x00E2
   apduResponse = try await commandSet.selectFile(fileId: ccFileId)
   _ = try apduResponse.checkOK()
   //Log the Apdu response
   exampleLogger.info(header: "APDU response", data: apduResponse.getData())
   
   let expectedLen: UInt16 = 0x10
   let offset: UInt16 = 0x0000
   apduResponse = try await commandSet.readBinary(offset: offset, expectedLen: expectedLen)
   _ = try apduResponse.checkOK()
   _ = apduResponse.getData() // Returns response data bytes
   //Log the Apdu response
   exampleLogger.info(header: "APDU response", data: apduResponse.getData())
   
   } catch let error as ApduError {
           print(error.localizedDescription)
   }
   

Architecture

This image shows the software architecture of the library.

Fig. 20 Software architecture of the NBT APDU Swift library.

Components

• Command set

  This command set acts as the API interface for the iOS application. This module is responsible for coordinating the building of APDU commands, sending the commands to the secure element through the communication interface, and receiving response from the secure element.

• Command builder

  The command builder helps in framing the command APDUs according to the OPTIGA™ Authenticate NBT applet specification.

• Response parser

  The response parser helps in decoding the response APDUs including response data and status word according to the OPTIGA™ Authenticate NBT applet specification.

Interaction

This UML sequence diagram describes the interaction between the components.

Fig. 21 Interaction between components of the NBT APDU Swift library.

Directory structure

The library directory is structured according to the Pitchfork Layout.

hsw-apdu-nbt-swift
|-- LICENSES/                       # Includes list of licenses used for the library package
|-- Sources/                        # Includes source files of the library
|-- docs/                           # Includes images and the generated API reference
|-- .gitignore                      # Library specific gitignore file
|-- .swiftlint.yml                  # Includes Swift lint configurations
|-- Package.swift                   # Includes build configurations of the library
`-- README.md                       # Overview of hsw-apdu-nbt-swift library

Dependencies

• hsw-apdu-swift

  The APDU Swift library helps in building the APDU command bytes and parses the APDU response bytes according to the ISO/IEC 7816-4 specification.

• hsw-utils-swift

  The utilities library provides the utility methods such as byte conversions, string conversions, and bit operations.

• apple/swift-docc-plugin

  This dependent library supports building documentation for the Swift library.