src/org/average/nfcauthcr/YkNeo.java

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