py14443a.crc

All Samples(3) | Call(3) | Derive(0) | Import(0)

Calculates the ISO-14443A CRC checksum

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        def crc(inbytes):
    """Calculates the ISO-14443A CRC checksum"""
    wCrc = 0x6363

    for i in range(len(inbytes)):
        byte = ord(inbytes[i])
        byte = (byte ^ (wCrc & 0x00FF))
        byte = ((byte ^ (byte << 4)) & 0xFF)
        wCrc = ((wCrc >> 8) ^ (byte << 8) ^ (byte << 3) ^ (byte >> 4)) & 0xFFFF

    res = chr(wCrc & 0xFF) + chr((wCrc >> 8) & 0xff)
    return res

src/m/u/museotouch-HEAD/app/museolib/libs/mifareauth.py museotouch(Download)

U_l = pycrypto1.bytes_to_long(uid[:4])
 
msg = "\x93\x70" + uid + py14443a.crc("\x93\x70" + uid)
print "R -> T:", hex_dump(msg)
select = nfc.transceive_bytes(msg)

# We turn the parity handling OFF when sending our own
# Our auth message is for key type A on block 4
msg = "\x60\x00" + py14443a.crc("\x60\x00")
nfc.configure(nfc.NDO_HANDLE_PARITY, False)
print "R -> T:", hex_dump(msg)

ks2 = crypto1.get_word(0, 1)
 
msg = "\x30\x00" + py14443a.crc("\x30\x00")
par = py14443a.parity(msg)