nist_challenge_response

#!/usr/bin/env python
"""
Test challenge-response, assumes a NIST PUB 198 A.2
20 bytes test vector in Slot 2 (variable input)
"""

import sys
import yubico

expected = \
    b'\x09\x22\xd3\x40\x5f\xaa\x3d\x19\x4f\x82' + \
    b'\xa4\x58\x30\x73\x7d\x5c\xc6\xc7\x5d\x24'

# turn on YubiKey debug if -v is given as an argument
debug = False
if len(sys.argv) > 1:
    debug = (sys.argv[1] == '-v')

# Look for and initialize the YubiKey
try:
    YK = yubico.find_yubikey(debug=debug)
    print("Version : %s " % YK.version())
    print("Serial  : %i" % YK.serial())
    print("")

    # Do challenge-response
    secret = b'Sample #2'.ljust(64, b'\0')
    print("Sending challenge : %s\n" % repr(secret))

    response = YK.challenge_response(secret, slot=2)
except yubico.yubico_exception.YubicoError as inst:
    print("ERROR: %s" % inst.reason)
    sys.exit(1)

print("Response :\n%s\n" % yubico.yubico_util.hexdump(response))

# Workaround for http://bugs.python.org/issue24596
del YK

# Check if the response matched the expected one
if response == expected:
    print("OK! Response matches the NIST PUB 198 A.2 expected response.")
    sys.exit(0)
else:
    print("ERROR! Response does NOT match the NIST PUB 198 A.2 expected response.")
    sys.exit(1)