Deno FFI bindings to the PC/SC API.

pcsc provides both Application Level and Low Level abstraction of the PC/SC API for accessing ISO-7816/ISO-14433 smartcards as used in Banking (EMV / Chip-and-PIN) cards, ID cards and Passports.

The Application Level abstraction offers a dev-friendly API based on concepts and objects such as Context, Reader, Card, CommandAPDU and ResponseAPDU. The Low Level API exists as a lightweight wrapper over the standard [PC/SC] API calls, useful when porting existing code.

A third layer, OpenMobileAPI [OMAPI], is still work-in-progress.

Status

Requires Deno 1.23.2 or greater, along with --unstable and --allow-ffi flags.

Currently tested on MAC (M1) and Windows 10 64bits. Should work on linux. Any problems, please raise issue at (https://github.com/cryptographix/pcsc-deno). PRs welcome.

Application-level API

Use the ContextProvider to establish a Context (connection) with PC/SC, list Readerss, connect to and communicate with Cards.

On Deno, ContextProvider defaults to the FFI implementation that requires --unstable and --allow-ffi flags to be added to deno run or deno test commands.

Example (see examples/selecf-mf.ts)

import { ContextProvider, CommandAPDU, PCSC, ISO7816, HEX } from 'https://deno.land/x/pcsc/mod.ts';

const context = ContextProvider.establishContext();

const readers = context.listReaders();

for (const reader of readers) {
  if (reader.isMute) {
    console.log(`Reader ${reader.name}: MUTE`)
  }
  else if (reader.isPresent) {
    const card = await reader.connect();

    const selectMF = CommandAPDU
      .from([ISO7816.CLA.ISO, ISO7816.INS.SelectFile, 0x00, 0x00]) // ISO SELECT
      .setData([0x3f, 0x00]);         // #3F 00 = MF

    const resp = await card.transmitAPDU(selectMF);

    if (resp.SW == ISO7816.SW.SUCCESS) {
      // success ..
      console.log(`Reader ${reader.name}: MF successfully selected`);

      console.log(HEX.toString(resp.data));
    } else {
      // something went wrong .. 
      console.error(`Reader ${reader.name}: error SW=${resp.SW.toString(16)}`);
    }

    await card.disconnect(PCSC.Disposition.UnpowerCard);
  }
  else {
    console.log(`Reader ${reader.name}: NO CARD`)
  }
}

context.shutdown();

Then, to run:

deno run --unstable --allow-ffi https://deno.land/x/pcsc/examples/select-mf.ts

API

Class: ContextProvider

The ContextProvider object is a singleton registry that provides access to the PCSC context.

method: establishContext()

Connect to the PC/SC daemon and returns a valid Context. On Deno, an instance of FFIContext will be returned.

Class: Context

Top level object that maintains a connection to the PC/SC daemon, and allows listing the available Card Readers, detection and notification of any changes to readers. After use, the shutdown method should be called, to release any allocated resources.

Method: listReaders()

listReaders scans PC/SC for a list of connected readers, and returns an array of Readerobjects.

Method: async waitForChange()

waitForChange waits for a change - card insertion/removal or reader plug/unplug. If a notify handler has been registered, that will be called once for each change detected. A timeout (ms) may be specified after which the method will automatically resolve.

Method: shutdown()

shutdown shutsdown all Readers and closed the connection to the PC/SC deamon

Property: onStatusChange

Set onStatusChange to receive notifications for reader/card events. The supplied callback will be called with a reader object and a status indicative of the motive (type of change).

Note: if onStatusChange is set before the first call to waitForChange, then the callback will be notified once for each reader detected, with status setup. From that point on, further calls to waitForChange will automatically detect any newly inserted (plugged-in) or removed (unplugged) readers and notify with setup ou shutdown status’s respectively.

Class: Reader

Method: async connect()

Attempt to connect to a card, and if successful, returns a Card object that will allow communication. A connection may be either SHARED or EXCLUSIVE.

Method: shutdown()

shutdown shutsdown and cleans up the reader object.

Method: async waitForChange()

Waits for a change with this reader such as card insertion, removal, connection or disconnection, returning, on completion, the current reader status. An optional timeout value (in ms) may be supplied, defaulting to “immediate” if absent.

Upon successful completion, waitforChange will update internal state that can be inspected from class properties such as state, status, as well as isPresent, isMute and isConnected.

Property: name

Returns reader name as string.

Property: state

Return PC/SC currentState bits, a set of StateFlag bits, as seen during most recent call to waitForChange

Property: status

Returns the reader status as seen during most recent call to waitForChange on Reader/Context, see Context.onStatusChange

Property: isPresent

Returns true if a card is present (inserted or within contactless range). See status property.

Property: isMute

Returns true if a non-responsive card is detected. See status property.

Property: isConnected

Returns true if a card is present AND connected. See status property.

Property: readerState (only on FFIReader class)

Returns an instance of PC/SC SCARDREADERSTATE containing name, current state flags and ATR.

Property: onStatusChange

Set onStatusChange to receive notifications for reader/card events, for current reader only.

Class: Card

Method: async transmit()

transmit sends a serialized APDU to the card and waits for a response. Both input and output APDUs are serialized byte buffers (Uint8Array).

Method: async transmitAPDU()

transmit serializes an APDUCommand object, transmits it to the card, waits for a response and deserializes an APDUResponse object.

Method: reconnect()

reconnect reestablishes a connection to the card using a new set of communication parameters (protocol, shareMode), and optionally resetting or powering-off the card during the reconnect process.

Method: disconnect()

disconnect closes this connection to the card, optionally resetting or powering-off the card.

Property: isConnected

Returns true if this card object is connected (initially true, becomes false after a disconnect).

Class: APDUCommand

Encapsulates an ISO7816 APDU command, allowing (de)serialization to/from byte buffers.

Constructor: APDUCommand()

Construct a new APDU command object, setting CLA, INS, P1, P2, optional DATA and LE, and extended options. If DATA is supplied, it can be an Uint8Array, an array or iterator that maps to Number[].

Additional options may be supplied:

Method: toBytes()

Serialize APDU command to a byte-buffer, correctly encoding the different ISO APDU classes (1-4).

If { isExtended: true } is passed to constructor, will serialize as extended-length (Lc/Le encoded on 3 bytes) when required, otherwise will serialize as normal (short) APDU.

Method: setCLA/setINS/setP1/setP2/setData/setLe

Fluent (chainable) methods for building an APDU from it’s constituent parts.

Method: static from()

Static decoder, parses a byte-like buffer into an APDUCommand object. Current only handles non-extended length APDUs.

Property: cla/ins/p1/p2/data/le

Public properties of the command APDU.

Class: APDUResponse

Encapsulates an ISO7816 APDU response, allowing (de)serialization to/from byte buffers.

Constructor: APDUResponse()

Construct a new APDU response object, setting SW and DATA. If DATA is supplied, it can be an Uint8Array, an array or iterator that maps to Number[].

Method: toBytes()

Serialize APDU response to a byte-buffer.

Method: setSW/setSW1/setSW2/setData

Fluent (chainable) methods for building a response APDU from it’s constituent parts.

Method: static from()

Static decoder, parses a byte-like buffer into an APDUResponse object.

Property: SW/data

Public (readonly) properties of the response APDU.

Low-level and legacy usage

pcsc also provides low-level access to PC/SC via the following methods:

Note: SCardGetStatusChange and SCardTransmit are async functions, but there are also synchronous versions that may be useful in certain circumstances.

links

[PC/SC] https://pcscworkgroup.com/specifications/

[OMAPI] https://globalplatform.org/wp-content/uploads/2016/11/GPD_Open_Mobile_API_Spec_v3.3_PublicRelease.pdf