fix pin auth and add setPin/changePin

example/pcsc_example.dart

@@ -27,6 +27,8 @@ class CtapCcid extends CtapDevice {
       }
       rapdu += await _card.transmit(Uint8List.fromList(capdu));
     } while (rapdu.length >= 2 && rapdu[rapdu.length - 2] == 0x61);
+    print('> ${hex.encode(capdu)}');
+    print('< ${hex.encode(rapdu)}');
     return CtapResponse(rapdu[0], rapdu.sublist(1, rapdu.length - 2));
   }
 }
@@ -53,6 +55,7 @@ void main() async {
     print(ctap.info.versions);
     final cp = await ClientPin.create(ctap);
     print(await cp.getPinRetries());
+    print(await cp.changePin('123456', '1234'));
 
     await card.disconnect(Disposition.resetCard);
   } finally {

lib/src/ctap2/base.dart

@@ -130,11 +130,12 @@ class Ctap2 {
     return CtapResponse(res.status, parseGetInfoResponse(res.data));
   }
 
-  Future<CtapResponse<ClientPinResponse>> clientPin(
+  Future<CtapResponse<ClientPinResponse?>> clientPin(
       ClientPinRequest request) async {
     final req = makeClientPinRequest(request);
     final res = await device.transceive(req);
-    return CtapResponse(res.status, parseClientPinResponse(res.data));
+    return CtapResponse(
+        res.status, res.data.isEmpty ? null : parseClientPinResponse(res.data));
   }
 
   /// Make the request to get info from the authenticator.

lib/src/ctap2/pin.dart

@@ -33,7 +33,7 @@ class PinProtocolV1 extends PinProtocol {
   @override
   int get version => 1;
 
-  final _aes = AesCbc.with128bits(
+  final _aes = AesCbc.with256bits(
       macAlgorithm: MacAlgorithm.empty,
       paddingAlgorithm: PaddingAlgorithm.zero);
 
@@ -153,7 +153,7 @@ enum ClientPinSubCommand {
   getPinToken(0x05),
   getPinUvAuthTokenUsingUvWithPermissions(0x06),
   getUvRetries(0x07),
-  getPinUvAuthTokenUsingPinWithPermissions(0x08);
+  getPinUvAuthTokenUsingPinWithPermissions(0x09);
 
   const ClientPinSubCommand(this.value);
 
@@ -225,7 +225,7 @@ class ClientPin {
     if (resp.status != 0) {
       throw Exception('ClientPin failed.');
     }
-    return _pinProtocol.encapsulate(resp.data.keyAgreement!);
+    return _pinProtocol.encapsulate(resp.data!.keyAgreement!);
   }
 
   /// Get a PIN/UV token from the authenticator.
@@ -235,13 +235,18 @@ class ClientPin {
   /// [permissionsRpId] is the RP ID to which the permissions apply.
   Future<List<int>> getPinToken(String pin,
       {List<ClientPinPermission>? permissions, String? permissionsRpId}) async {
+    if (!ClientPin.isSupported(_ctap.info)) {
+      throw Exception('getPinToken is not supported.');
+    }
+
     final EncapsulateResult ss = await _getSharedSecret();
     final pinHash =
         (await Sha256().hash(utf8.encode(pin))).bytes.sublist(0, 16);
     final pinHashEnc = await _pinProtocol.encrypt(ss.sharedSecret, pinHash);
 
     int subCmd = ClientPinSubCommand.getPinToken.value;
     if (ClientPin.isTokenSupported(_ctap.info)) {
+      assert(permissions != null);
       subCmd =
           ClientPinSubCommand.getPinUvAuthTokenUsingPinWithPermissions.value;
     }
@@ -255,14 +260,69 @@ class ClientPin {
         rpId: permissionsRpId));
 
     return await _pinProtocol.decrypt(
-        ss.sharedSecret, resp.data.pinUvAuthToken!);
+        ss.sharedSecret, resp.data!.pinUvAuthToken!);
   }
 
   /// Get the number of PIN retries remaining.
   Future<int> getPinRetries() async {
+    if (!ClientPin.isSupported(_ctap.info)) {
+      throw Exception('getPinRetries is not supported.');
+    }
+
     final resp = await _ctap.clientPin(ClientPinRequest(
         pinUvAuthProtocol: _pinProtocol.version,
         subCommand: ClientPinSubCommand.getPinRetries.value));
-    return resp.data.pinRetries!;
+    return resp.data!.pinRetries!;
+  }
+
+  /// Set the [pin] of the authenticator.
+  ///
+  ///  This only works when no PIN is set. To change the PIN when set, use changePin.
+  Future<bool> setPin(String pin) async {
+    if (!ClientPin.isSupported(_ctap.info)) {
+      throw Exception('setPin is not supported.');
+    }
+
+    final EncapsulateResult ss = await _getSharedSecret();
+    final pinEnc = await _pinProtocol.encrypt(ss.sharedSecret, _padPin(pin));
+    final pinUvAuthParam =
+        await _pinProtocol.authenticate(ss.sharedSecret, pinEnc);
+    final resp = await _ctap.clientPin(ClientPinRequest(
+        pinUvAuthProtocol: _pinProtocol.version,
+        subCommand: ClientPinSubCommand.setPin.value,
+        newPinEnc: pinEnc,
+        pinUvAuthParam: pinUvAuthParam));
+    return resp.status == 0;
+  }
+
+  /// Change the PIN of the authenticator.
+  /// This only works when a PIN is already set. If no PIN is set, use setPin.
+  Future<bool> changePin(String oldPin, String newPin) async {
+    if (!ClientPin.isSupported(_ctap.info)) {
+      throw Exception('changePin is not supported.');
+    }
+
+    final EncapsulateResult ss = await _getSharedSecret();
+    final pinHash =
+        (await Sha256().hash(utf8.encode(oldPin))).bytes.sublist(0, 16);
+    final pinHashEnc = await _pinProtocol.encrypt(ss.sharedSecret, pinHash);
+    final newPinEnc =
+        await _pinProtocol.encrypt(ss.sharedSecret, _padPin(newPin));
+    final pinUvAuthParam = await _pinProtocol.authenticate(
+        ss.sharedSecret, newPinEnc + pinHashEnc);
+    final resp = await _ctap.clientPin(ClientPinRequest(
+        pinUvAuthProtocol: _pinProtocol.version,
+        subCommand: ClientPinSubCommand.changePin.value,
+        keyAgreement: ss.coseKey,
+        pinHashEnc: pinHashEnc,
+        newPinEnc: newPinEnc,
+        pinUvAuthParam: pinUvAuthParam));
+    return resp.status == 0;
+  }
+
+  /// Pad the PIN to 64 bytes.
+  List<int> _padPin(String pin) {
+    final pinBytes = utf8.encode(pin);
+    return pinBytes + List.filled(64 - pinBytes.length, 0);
   }
 }

test/fido2_pin_test.dart

@@ -3,7 +3,6 @@ import 'package:cryptography/cryptography.dart';
 import 'package:elliptic/ecdh.dart';
 import 'package:elliptic/elliptic.dart';
 import 'package:fido2/fido2.dart';
-import 'package:fido2/src/cose.dart';
 import 'package:test/test.dart';
 
 import 'fido2_ctap.dart';
@@ -29,17 +28,19 @@ void main() {
     });
 
     test('encrypt', () async {
-      final key = hex.decode('000102030405060708090a0b0c0d0e0f');
+      final key = hex.decode(
+          '000102030405060708090a0b0c0d0e0f000102030405060708090a0b0c0d0e0f');
       final plaintext = hex.decode('00112233445566778899aabbccddeeff');
-      final ciphertext = hex.decode('69c4e0d86a7b0430d8cdb78070b4c55a');
+      final ciphertext = hex.decode('04a121e92033c921048917754f961b0d');
       PinProtocolV1 pinProtocol = PinProtocolV1();
       expect(await pinProtocol.encrypt(key, plaintext), equals(ciphertext));
     });
 
     test('decrypt', () async {
-      final key = hex.decode('000102030405060708090a0b0c0d0e0f');
+      final key = hex.decode(
+          '000102030405060708090a0b0c0d0e0f000102030405060708090a0b0c0d0e0f');
       final plaintext = hex.decode('00112233445566778899aabbccddeeff');
-      final ciphertext = hex.decode('69c4e0d86a7b0430d8cdb78070b4c55a');
+      final ciphertext = hex.decode('04a121e92033c921048917754f961b0d');
       PinProtocolV1 pinProtocol = PinProtocolV1();
       expect(await pinProtocol.decrypt(key, ciphertext), equals(plaintext));
     });