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# Copyright (c) 2015, Legrandin <helderijs@gmail.com>
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import json
import unittest
from binascii import unhexlify

from Crypto.SelfTest.st_common import list_test_cases
from Crypto.Util.py3compat import tobytes, bchr
from Crypto.Cipher import AES
from Crypto.Hash import SHAKE128

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


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


class SivTests(unittest.TestCase):

    key_256 = get_tag_random("key_256", 32)
    key_384 = get_tag_random("key_384", 48)
    key_512 = get_tag_random("key_512", 64)
    nonce_96 = get_tag_random("nonce_128", 12)
    data_128 = get_tag_random("data_128", 16)

    def test_loopback_128(self):
        for key in self.key_256, self.key_384, self.key_512:
            cipher = AES.new(key, AES.MODE_SIV, nonce=self.nonce_96)
            pt = get_tag_random("plaintext", 16 * 100)
            ct, mac = cipher.encrypt_and_digest(pt)

            cipher = AES.new(key, AES.MODE_SIV, nonce=self.nonce_96)
            pt2 = cipher.decrypt_and_verify(ct, mac)
            self.assertEqual(pt, pt2)

    def test_nonce(self):
        # Deterministic encryption
        AES.new(self.key_256, AES.MODE_SIV)

        cipher = AES.new(self.key_256, AES.MODE_SIV, self.nonce_96)
        ct1, tag1 = cipher.encrypt_and_digest(self.data_128)

        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        ct2, tag2 = cipher.encrypt_and_digest(self.data_128)
        self.assertEquals(ct1 + tag1, ct2 + tag2)

    def test_nonce_must_be_bytes(self):
        self.assertRaises(TypeError, AES.new, self.key_256, AES.MODE_SIV,
                          nonce=u'test12345678')

    def test_nonce_length(self):
        # nonce can be of any length (but not empty)
        self.assertRaises(ValueError, AES.new, self.key_256, AES.MODE_SIV,
                          nonce=b"")

        for x in range(1, 128):
            cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=bchr(1) * x)
            cipher.encrypt_and_digest(b'\x01')

    def test_block_size_128(self):
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        self.assertEqual(cipher.block_size, AES.block_size)

    def test_nonce_attribute(self):
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        self.assertEqual(cipher.nonce, self.nonce_96)

        # By default, no nonce is randomly generated
        self.failIf(hasattr(AES.new(self.key_256, AES.MODE_SIV), "nonce"))

    def test_unknown_parameters(self):
        self.assertRaises(TypeError, AES.new, self.key_256, AES.MODE_SIV,
                          self.nonce_96, 7)
        self.assertRaises(TypeError, AES.new, self.key_256, AES.MODE_SIV,
                          nonce=self.nonce_96, unknown=7)

        # But some are only known by the base cipher
        # (e.g. use_aesni consumed by the AES module)
        AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96,
                use_aesni=False)

    def test_encrypt_excludes_decrypt(self):
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        cipher.encrypt_and_digest(self.data_128)
        self.assertRaises(TypeError, cipher.decrypt, self.data_128)

        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        cipher.encrypt_and_digest(self.data_128)
        self.assertRaises(TypeError, cipher.decrypt_and_verify,
                          self.data_128, self.data_128)

    def test_data_must_be_bytes(self):
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        self.assertRaises(TypeError, cipher.encrypt, u'test1234567890-*')

        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        self.assertRaises(TypeError, cipher.decrypt_and_verify,
                          u'test1234567890-*', b"xxxx")

    def test_mac_len(self):
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        _, mac = cipher.encrypt_and_digest(self.data_128)
        self.assertEqual(len(mac), 16)

    def test_invalid_mac(self):
        from Crypto.Util.strxor import strxor_c
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        ct, mac = cipher.encrypt_and_digest(self.data_128)

        invalid_mac = strxor_c(mac, 0x01)

        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        self.assertRaises(ValueError, cipher.decrypt_and_verify, ct,
                          invalid_mac)

    def test_hex_mac(self):
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        mac_hex = cipher.hexdigest()
        self.assertEqual(cipher.digest(), unhexlify(mac_hex))

        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        cipher.hexverify(mac_hex)
    
    def test_bytearray(self):

        # Encrypt
        key = bytearray(self.key_256)
        nonce = bytearray(self.nonce_96)
        data = bytearray(self.data_128)
        header = bytearray(self.data_128)
        
        cipher1 = AES.new(self.key_256,
                          AES.MODE_SIV,
                          nonce=self.nonce_96)
        cipher1.update(self.data_128)
        ct, tag = cipher1.encrypt_and_digest(self.data_128)

        cipher2 = AES.new(key,
                          AES.MODE_SIV,
                          nonce=nonce)
        key[:3] = b'\xFF\xFF\xFF'
        nonce[:3] = b'\xFF\xFF\xFF'
        cipher2.update(header)
        header[:3] = b'\xFF\xFF\xFF'
        ct_test, tag_test = cipher2.encrypt_and_digest(data)

        self.assertEqual(ct, ct_test)
        self.assertEqual(tag, tag_test)
        self.assertEqual(cipher1.nonce, cipher2.nonce)

        # Decrypt
        key = bytearray(self.key_256)
        nonce = bytearray(self.nonce_96)
        header = bytearray(self.data_128)
        ct_ba = bytearray(ct)
        tag_ba = bytearray(tag)
        
        cipher3 = AES.new(key,
                          AES.MODE_SIV,
                          nonce=nonce)
        key[:3] = b'\xFF\xFF\xFF'
        nonce[:3] = b'\xFF\xFF\xFF'
        cipher3.update(header)
        header[:3] = b'\xFF\xFF\xFF'
        pt_test = cipher3.decrypt_and_verify(ct_ba, tag_ba)

        self.assertEqual(self.data_128, pt_test)
    
    def test_memoryview(self):

        # Encrypt
        key = memoryview(bytearray(self.key_256))
        nonce = memoryview(bytearray(self.nonce_96))
        data = memoryview(bytearray(self.data_128))
        header = memoryview(bytearray(self.data_128))
        
        cipher1 = AES.new(self.key_256,
                          AES.MODE_SIV,
                          nonce=self.nonce_96)
        cipher1.update(self.data_128)
        ct, tag = cipher1.encrypt_and_digest(self.data_128)

        cipher2 = AES.new(key,
                          AES.MODE_SIV,
                          nonce=nonce)
        key[:3] = b'\xFF\xFF\xFF'
        nonce[:3] = b'\xFF\xFF\xFF'
        cipher2.update(header)
        header[:3] = b'\xFF\xFF\xFF'
        ct_test, tag_test= cipher2.encrypt_and_digest(data)

        self.assertEqual(ct, ct_test)
        self.assertEqual(tag, tag_test)
        self.assertEqual(cipher1.nonce, cipher2.nonce)

        # Decrypt
        key = memoryview(bytearray(self.key_256))
        nonce = memoryview(bytearray(self.nonce_96))
        header = memoryview(bytearray(self.data_128))
        ct_ba = memoryview(bytearray(ct))
        tag_ba = memoryview(bytearray(tag))
        
        cipher3 = AES.new(key,
                          AES.MODE_SIV,
                          nonce=nonce)
        key[:3] = b'\xFF\xFF\xFF'
        nonce[:3] = b'\xFF\xFF\xFF'
        cipher3.update(header)
        header[:3] = b'\xFF\xFF\xFF'
        pt_test = cipher3.decrypt_and_verify(ct_ba, tag_ba)

        self.assertEqual(self.data_128, pt_test)
    
    def test_output_param(self):

        pt = b'5' * 16
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        ct, tag = cipher.encrypt_and_digest(pt)

        output = bytearray(16)
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        res, tag_out = cipher.encrypt_and_digest(pt, output=output)
        self.assertEqual(ct, output)
        self.assertEqual(res, None)
        self.assertEqual(tag, tag_out)
        
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        res = cipher.decrypt_and_verify(ct, tag, output=output)
        self.assertEqual(pt, output)
        self.assertEqual(res, None)

    def test_output_param_memoryview(self):
        
        pt = b'5' * 16
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        ct, tag = cipher.encrypt_and_digest(pt)

        output = memoryview(bytearray(16))
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        cipher.encrypt_and_digest(pt, output=output)
        self.assertEqual(ct, output)
        
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        cipher.decrypt_and_verify(ct, tag, output=output)
        self.assertEqual(pt, output)

    def test_output_param_neg(self):

        pt = b'5' * 16
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        ct, tag = cipher.encrypt_and_digest(pt)

        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        self.assertRaises(TypeError, cipher.encrypt_and_digest, pt, output=b'0'*16)
        
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        self.assertRaises(TypeError, cipher.decrypt_and_verify, ct, tag, output=b'0'*16)

        shorter_output = bytearray(15)
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        self.assertRaises(ValueError, cipher.encrypt_and_digest, pt, output=shorter_output)
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        self.assertRaises(ValueError, cipher.decrypt_and_verify, ct, tag, output=shorter_output)


    import sys
    if sys.version[:3] == "2.6":
        del test_memoryview
        del test_output_param_memoryview


class SivFSMTests(unittest.TestCase):

    key_256 = get_tag_random("key_256", 32)
    nonce_96 = get_tag_random("nonce_96", 12)
    data_128 = get_tag_random("data_128", 16)
    
    def test_invalid_init_encrypt(self):
        # Path INIT->ENCRYPT fails
        cipher = AES.new(self.key_256, AES.MODE_SIV,
                         nonce=self.nonce_96)
        self.assertRaises(TypeError, cipher.encrypt, b"xxx")

    def test_invalid_init_decrypt(self):
        # Path INIT->DECRYPT fails
        cipher = AES.new(self.key_256, AES.MODE_SIV,
                         nonce=self.nonce_96)
        self.assertRaises(TypeError, cipher.decrypt, b"xxx")

    def test_valid_init_update_digest_verify(self):
        # No plaintext, fixed authenticated data
        # Verify path INIT->UPDATE->DIGEST
        cipher = AES.new(self.key_256, AES.MODE_SIV,
                         nonce=self.nonce_96)
        cipher.update(self.data_128)
        mac = cipher.digest()

        # Verify path INIT->UPDATE->VERIFY
        cipher = AES.new(self.key_256, AES.MODE_SIV,
                         nonce=self.nonce_96)
        cipher.update(self.data_128)
        cipher.verify(mac)

    def test_valid_init_digest(self):
        # Verify path INIT->DIGEST
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        cipher.digest()

    def test_valid_init_verify(self):
        # Verify path INIT->VERIFY
        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        mac = cipher.digest()

        cipher = AES.new(self.key_256, AES.MODE_SIV, nonce=self.nonce_96)
        cipher.verify(mac)