#
#  SelfTest/Hash/CMAC.py: Self-test for the CMAC module
#
# ===================================================================
#
# Copyright (c) 2014, Legrandin <helderijs@gmail.com>
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# modification, are permitted provided that the following conditions
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# 1. Redistributions of source code must retain the above copyright
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"""Self-test suite for Crypto.Hash.CMAC"""

import json
import unittest
from binascii import unhexlify

from Crypto.Util.py3compat import tobytes, _memoryview

from Crypto.Hash import CMAC
from Crypto.Cipher import AES, DES3
from Crypto.Hash import SHAKE128

from Crypto.Util._file_system import pycryptodome_filename
from Crypto.Util.strxor import strxor

from Crypto.SelfTest.st_common import list_test_cases

# This is a list of (key, data, result, description, module) tuples.
test_data = [

    ## Test vectors from RFC 4493 ##
    ## The are also in NIST SP 800 38B D.2 ##
    (   '2b7e151628aed2a6abf7158809cf4f3c',
        '',
        'bb1d6929e95937287fa37d129b756746',
        'RFC 4493 #1',
        AES
    ),

    (   '2b7e151628aed2a6abf7158809cf4f3c',
        '6bc1bee22e409f96e93d7e117393172a',
        '070a16b46b4d4144f79bdd9dd04a287c',
        'RFC 4493 #2',
        AES
    ),

    (   '2b7e151628aed2a6abf7158809cf4f3c',
        '6bc1bee22e409f96e93d7e117393172a'+
        'ae2d8a571e03ac9c9eb76fac45af8e51'+
        '30c81c46a35ce411',
        'dfa66747de9ae63030ca32611497c827',
        'RFC 4493 #3',
        AES
    ),

    (   '2b7e151628aed2a6abf7158809cf4f3c',
        '6bc1bee22e409f96e93d7e117393172a'+
        'ae2d8a571e03ac9c9eb76fac45af8e51'+
        '30c81c46a35ce411e5fbc1191a0a52ef'+
        'f69f2445df4f9b17ad2b417be66c3710',
        '51f0bebf7e3b9d92fc49741779363cfe',
        'RFC 4493 #4',
        AES
    ),

    ## The rest of Appendix D of NIST SP 800 38B
    ## was not totally correct.
    ## Values in Examples 14, 15, 18, and 19 were wrong.
    ## The updated test values are published in:
    ## http://csrc.nist.gov/publications/nistpubs/800-38B/Updated_CMAC_Examples.pdf

    (   '8e73b0f7da0e6452c810f32b809079e5'+
        '62f8ead2522c6b7b',
        '',
        'd17ddf46adaacde531cac483de7a9367',
        'NIST SP 800 38B D.2 Example 5',
        AES
    ),

    (   '8e73b0f7da0e6452c810f32b809079e5'+
        '62f8ead2522c6b7b',
        '6bc1bee22e409f96e93d7e117393172a',
        '9e99a7bf31e710900662f65e617c5184',
        'NIST SP 800 38B D.2 Example 6',
        AES
    ),

    (   '8e73b0f7da0e6452c810f32b809079e5'+
        '62f8ead2522c6b7b',
        '6bc1bee22e409f96e93d7e117393172a'+
        'ae2d8a571e03ac9c9eb76fac45af8e51'+
        '30c81c46a35ce411',
        '8a1de5be2eb31aad089a82e6ee908b0e',
        'NIST SP 800 38B D.2 Example 7',
        AES
    ),

    (   '8e73b0f7da0e6452c810f32b809079e5'+
        '62f8ead2522c6b7b',
        '6bc1bee22e409f96e93d7e117393172a'+
        'ae2d8a571e03ac9c9eb76fac45af8e51'+
        '30c81c46a35ce411e5fbc1191a0a52ef'+
        'f69f2445df4f9b17ad2b417be66c3710',
        'a1d5df0eed790f794d77589659f39a11',
        'NIST SP 800 38B D.2 Example 8',
        AES
    ),

    (   '603deb1015ca71be2b73aef0857d7781'+
        '1f352c073b6108d72d9810a30914dff4',
        '',
        '028962f61b7bf89efc6b551f4667d983',
        'NIST SP 800 38B D.3 Example 9',
        AES
    ),

    (   '603deb1015ca71be2b73aef0857d7781'+
        '1f352c073b6108d72d9810a30914dff4',
        '6bc1bee22e409f96e93d7e117393172a',
        '28a7023f452e8f82bd4bf28d8c37c35c',
        'NIST SP 800 38B D.3 Example 10',
        AES
    ),

    (   '603deb1015ca71be2b73aef0857d7781'+
        '1f352c073b6108d72d9810a30914dff4',
        '6bc1bee22e409f96e93d7e117393172a'+
        'ae2d8a571e03ac9c9eb76fac45af8e51'+
        '30c81c46a35ce411',
        'aaf3d8f1de5640c232f5b169b9c911e6',
        'NIST SP 800 38B D.3 Example 11',
        AES
    ),

    (   '603deb1015ca71be2b73aef0857d7781'+
        '1f352c073b6108d72d9810a30914dff4',
        '6bc1bee22e409f96e93d7e117393172a'+
        'ae2d8a571e03ac9c9eb76fac45af8e51'+
        '30c81c46a35ce411e5fbc1191a0a52ef'+
        'f69f2445df4f9b17ad2b417be66c3710',
        'e1992190549f6ed5696a2c056c315410',
        'NIST SP 800 38B D.3 Example 12',
        AES
    ),

    (   '8aa83bf8cbda1062'+
        '0bc1bf19fbb6cd58'+
        'bc313d4a371ca8b5',
        '',
        'b7a688e122ffaf95',
        'NIST SP 800 38B D.4 Example 13',
        DES3
    ),

    (   '8aa83bf8cbda1062'+
        '0bc1bf19fbb6cd58'+
        'bc313d4a371ca8b5',
        '6bc1bee22e409f96',
        '8e8f293136283797',
        'NIST SP 800 38B D.4 Example 14',
        DES3
    ),

    (   '8aa83bf8cbda1062'+
        '0bc1bf19fbb6cd58'+
        'bc313d4a371ca8b5',
        '6bc1bee22e409f96'+
        'e93d7e117393172a'+
        'ae2d8a57',
        '743ddbe0ce2dc2ed',
        'NIST SP 800 38B D.4 Example 15',
        DES3
    ),

    (   '8aa83bf8cbda1062'+
        '0bc1bf19fbb6cd58'+
        'bc313d4a371ca8b5',
        '6bc1bee22e409f96'+
        'e93d7e117393172a'+
        'ae2d8a571e03ac9c'+
        '9eb76fac45af8e51',
        '33e6b1092400eae5',
        'NIST SP 800 38B D.4 Example 16',
        DES3
    ),

    (   '4cf15134a2850dd5'+
        '8a3d10ba80570d38',
        '',
        'bd2ebf9a3ba00361',
        'NIST SP 800 38B D.7 Example 17',
        DES3
    ),

    (   '4cf15134a2850dd5'+
        '8a3d10ba80570d38',
        '6bc1bee22e409f96',
        '4ff2ab813c53ce83',
        'NIST SP 800 38B D.7 Example 18',
        DES3
    ),

    (   '4cf15134a2850dd5'+
        '8a3d10ba80570d38',
        '6bc1bee22e409f96'+
        'e93d7e117393172a'+
        'ae2d8a57',
        '62dd1b471902bd4e',
        'NIST SP 800 38B D.7 Example 19',
        DES3
    ),

    (   '4cf15134a2850dd5'+
        '8a3d10ba80570d38',
        '6bc1bee22e409f96'+
        'e93d7e117393172a'+
        'ae2d8a571e03ac9c'+
        '9eb76fac45af8e51',
        '31b1e431dabc4eb8',
        'NIST SP 800 38B D.7 Example 20',
        DES3
    ),

]


def get_tag_random(tag, length):
    return SHAKE128.new(data=tobytes(tag)).read(length)


class TestCMAC(unittest.TestCase):

    def test_internal_caching(self):
        """Verify that internal caching is implemented correctly"""

        data_to_mac = get_tag_random("data_to_mac", 128)
        key = get_tag_random("key", 16)
        ref_mac = CMAC.new(key, msg=data_to_mac, ciphermod=AES).digest()

        # Break up in chunks of different length
        # The result must always be the same
        for chunk_length in 1, 2, 3, 7, 10, 13, 16, 40, 80, 128:

            chunks = [data_to_mac[i:i+chunk_length] for i in
                      range(0, len(data_to_mac), chunk_length)]

            mac = CMAC.new(key, ciphermod=AES)
            for chunk in chunks:
                mac.update(chunk)
            self.assertEqual(ref_mac, mac.digest())

    def test_update_after_digest(self):
        msg = b"rrrrttt"
        key = b"4" * 16

        # Normally, update() cannot be done after digest()
        h = CMAC.new(key, msg[:4], ciphermod=AES)
        dig1 = h.digest()
        self.assertRaises(TypeError, h.update, msg[4:])
        dig2 = CMAC.new(key, msg, ciphermod=AES).digest()

        # With the proper flag, it is allowed
        h2 = CMAC.new(key, msg[:4], ciphermod=AES, update_after_digest=True)
        self.assertEquals(h2.digest(), dig1)
        # ... and the subsequent digest applies to the entire message
        # up to that point
        h2.update(msg[4:])
        self.assertEquals(h2.digest(), dig2)


class ByteArrayTests(unittest.TestCase):

    def runTest(self):

        key = b"0" * 16
        data = b"\x00\x01\x02"

        # Data and key can be a bytearray (during initialization)
        key_ba = bytearray(key)
        data_ba = bytearray(data)

        h1 = CMAC.new(key, data, ciphermod=AES)
        h2 = CMAC.new(key_ba, data_ba, ciphermod=AES)
        key_ba[:1] = b'\xFF'
        data_ba[:1] = b'\xFF'
        self.assertEqual(h1.digest(), h2.digest())

        # Data can be a bytearray (during operation)
        key_ba = bytearray(key)
        data_ba = bytearray(data)

        h1 = CMAC.new(key, ciphermod=AES)
        h2 = CMAC.new(key, ciphermod=AES)
        h1.update(data)
        h2.update(data_ba)
        data_ba[:1] = b'\xFF'
        self.assertEqual(h1.digest(), h2.digest())


class MemoryViewTests(unittest.TestCase):

    def runTest(self):

        key = b"0" * 16
        data = b"\x00\x01\x02"

        def get_mv_ro(data):
            return memoryview(data)

        def get_mv_rw(data):
            return memoryview(bytearray(data))

        for get_mv in (get_mv_ro, get_mv_rw):

            # Data and key can be a memoryview (during initialization)
            key_mv = get_mv(key)
            data_mv = get_mv(data)

            h1 = CMAC.new(key, data, ciphermod=AES)
            h2 = CMAC.new(key_mv, data_mv, ciphermod=AES)
            if not data_mv.readonly:
                key_mv[:1] = b'\xFF'
                data_mv[:1] = b'\xFF'
            self.assertEqual(h1.digest(), h2.digest())

            # Data can be a memoryview (during operation)
            data_mv = get_mv(data)

            h1 = CMAC.new(key, ciphermod=AES)
            h2 = CMAC.new(key, ciphermod=AES)
            h1.update(data)
            h2.update(data_mv)
            if not data_mv.readonly:
                data_mv[:1] = b'\xFF'
            self.assertEqual(h1.digest(), h2.digest())


class TestVectorsWycheproof(unittest.TestCase):

    def __init__(self, wycheproof_warnings):
        unittest.TestCase.__init__(self)
        self._wycheproof_warnings = wycheproof_warnings
        self._id = "None"

    def setUp(self):
        comps = "Crypto.SelfTest.Hash.test_vectors.wycheproof".split(".")
        with open(pycryptodome_filename(comps, "aes_cmac_test.json"), "rt") as file_in:
            tv_tree = json.load(file_in)

        class TestVector(object):
            pass
        self.tv = []

        for group in tv_tree['testGroups']:
            tag_size = group['tagSize'] // 8
            for test in group['tests']:
                tv = TestVector()
                tv.tag_size = tag_size

                tv.id = test['tcId']
                tv.comment = test['comment']
                for attr in 'key', 'msg', 'tag':
                    setattr(tv, attr, unhexlify(test[attr]))
                tv.valid = test['result'] != "invalid"
                tv.warning = test['result'] == "acceptable"
                self.tv.append(tv)

    def shortDescription(self):
        return self._id

    def warn(self, tv):
        if tv.warning and self._wycheproof_warnings:
            import warnings
            warnings.warn("Wycheproof warning: %s (%s)" % (self._id, tv.comment))

    def test_create_mac(self, tv):
        self._id = "Wycheproof MAC creation Test #" + str(tv.id)
        
        try:
            tag = CMAC.new(tv.key, tv.msg, ciphermod=AES, mac_len=tv.tag_size).digest()
        except ValueError as e:
            if len(tv.key) not in (16, 24, 32) and "key length" in str(e):
                return
            raise e
        if tv.valid:
            self.assertEqual(tag, tv.tag)
            self.warn(tv)

    def test_verify_mac(self, tv):
        self._id = "Wycheproof MAC verification Test #" + str(tv.id)
       
        try:
            mac = CMAC.new(tv.key, tv.msg, ciphermod=AES, mac_len=tv.tag_size)
        except ValueError as e:
            if len(tv.key) not in (16, 24, 32) and "key length" in str(e):
                return
            raise e
        try:
            mac.verify(tv.tag)
        except ValueError:
            assert not tv.valid
        else:
            assert tv.valid
            self.warn(tv)

    def runTest(self):

        for tv in self.tv:
            self.test_create_mac(tv)
            self.test_verify_mac(tv)


def get_tests(config={}):
    global test_data
    import types
    from .common import make_mac_tests
    
    wycheproof_warnings = config.get('wycheproof_warnings')

    # Add new() parameters to the back of each test vector
    params_test_data = []
    for row in test_data:
        t = list(row)
        t[4] = dict(ciphermod=t[4])
        params_test_data.append(t)

    tests = make_mac_tests(CMAC, "CMAC", params_test_data)
    tests.append(ByteArrayTests())
    tests.append(list_test_cases(TestCMAC))
    
    import sys
    if sys.version[:3] != "2.6":
        tests.append(MemoryViewTests())
    
    tests += [ TestVectorsWycheproof(wycheproof_warnings) ]
    return tests


if __name__ == '__main__':
    import unittest
    suite = lambda: unittest.TestSuite(get_tests())
    unittest.main(defaultTest='suite')