src/org/average/nfcauthcr/YkNeo.java

   1 package org.average.nfcauthcr;
   2
   3 import java.lang.String;
   4 import java.io.IOException;
   5 import java.util.Arrays;
   6
   7 import android.nfc.NfcAdapter;
   8 import android.nfc.Tag;
   9 import android.nfc.TagLostException;
  10 import android.nfc.tech.IsoDep;
  11
  12 import org.average.nfcauthcr.CRException;
  13
  14 public class YkNeo {
  15
  16         // This is a CCID APDU, ISO 7816-4.
  17         // 00 A4 04 00 xx AID - GlobalPlatform - SELECT
  18         // Lc, send data = 07: A0 00 00 05 27 20 01
  19         // Le, recv data = 00
  20         private static final byte[] selectApdu =
  21                 {0x00, (byte) 0xA4, 0x04, 0x00, 0x07, (byte) 0xA0,
  22                  0x00, 0x00, 0x05, 0x27, 0x20, 0x01, 0x00};
  23
  24         private static final byte SLOT_CHAL_HMAC1 = 0x30;
  25         private static final byte SLOT_CHAL_HMAC2 = 0x38;
  26
  27         public static final byte[] doChallengeYubiKey(IsoDep isoTag, int slot,
  28                                                 byte[] challenge)
  29                                 throws CRException {
  30                 try {
  31                         isoTag.connect();
  32                         byte[] resp = isoTag.transceive(selectApdu);
  33                         int length = resp.length;
  34                         if (resp[length - 2] != (byte)0x90 ||
  35                             resp[length - 1] != 0x00) {
  36                                 throw new CRException(String.format(
  37                                 "NFC select error code: %02x:%02x",
  38                                 resp[length - 2], resp[length - 1]));
  39                         }
  40                         byte[] crApdu = new byte[69];
  41                         crApdu[0] = 0x00; // CLA
  42                         crApdu[1] = 0x01; // INS
  43                         switch (slot) {
  44                         case 1: crApdu[2] = SLOT_CHAL_HMAC1; break; // P1
  45                         case 2: crApdu[2] = SLOT_CHAL_HMAC2; break; // P1
  46                         }
  47                         crApdu[3] = 0x00; // P2
  48                         crApdu[4] = 63;   // Lc
  49                         System.arraycopy(challenge, 0, crApdu, 5,
  50                                                 challenge.length); // Payload
  51                         crApdu[crApdu.length-1] = 22; // Le
  52                         resp = isoTag.transceive(crApdu);
  53                         length = resp.length;
  54                         if (resp[length - 2] != (byte)0x90 ||
  55                             resp[length - 1] != 0x00) {
  56                                 throw new CRException(String.format(
  57                                 "NFC CR error code: %02x:%02x",
  58                                 resp[length - 2], resp[length - 1]));
  59                         }
  60                         if (length != 22) {
  61                                 throw new CRException(String.format(
  62                                 "NFC wrong response size: got %d, need 20",
  63                                 length-2));
  64                         }
  65                         return Arrays.copyOf(resp, length-2);
  66                 } catch (TagLostException e) {
  67                         throw new CRException("NFC connection lost", e);
  68                 } catch (IOException e) {
  69                         throw new CRException("NFC I/O: " + e.getMessage(), e);
  70                 }
  71         }
  72 }