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# Copyright 2016 Donald Stufft and individual contributors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import binascii
from typing import Callable, Dict, List, NamedTuple, Optional
from hypothesis import given, settings
from hypothesis.strategies import binary, sampled_from
import pytest
import nacl.bindings as b
import nacl.exceptions as exc
from .utils import read_kv_test_vectors
def chacha20poly1305_agl_vectors() -> List[Dict[str, bytes]]:
# NIST vectors derived format
DATA = "chacha20-poly1305-agl_ref.txt"
return read_kv_test_vectors(DATA, delimiter=b":", newrecord=b"AEAD")
def chacha20poly1305_ietf_vectors() -> List[Dict[str, bytes]]:
# NIST vectors derived format
DATA = "chacha20-poly1305-ietf_ref.txt"
return read_kv_test_vectors(DATA, delimiter=b":", newrecord=b"AEAD")
def xchacha20poly1305_ietf_vectors() -> List[Dict[str, bytes]]:
# NIST vectors derived format
DATA = "xchacha20-poly1305-ietf_ref.txt"
return read_kv_test_vectors(DATA, delimiter=b":", newrecord=b"AEAD")
class Construction(NamedTuple):
encrypt: Callable[[bytes, Optional[bytes], bytes, bytes], bytes]
decrypt: Callable[[bytes, Optional[bytes], bytes, bytes], bytes]
NPUB: int
KEYBYTES: int
def _getconstruction(construction: bytes) -> Construction:
if construction == b"chacha20-poly1305-old":
encrypt = b.crypto_aead_chacha20poly1305_encrypt
decrypt = b.crypto_aead_chacha20poly1305_decrypt
NPUB = b.crypto_aead_chacha20poly1305_NPUBBYTES
KEYBYTES = b.crypto_aead_chacha20poly1305_KEYBYTES
elif construction == b"chacha20-poly1305":
encrypt = b.crypto_aead_chacha20poly1305_ietf_encrypt
decrypt = b.crypto_aead_chacha20poly1305_ietf_decrypt
NPUB = b.crypto_aead_chacha20poly1305_ietf_NPUBBYTES
KEYBYTES = b.crypto_aead_chacha20poly1305_ietf_KEYBYTES
else:
encrypt = b.crypto_aead_xchacha20poly1305_ietf_encrypt
decrypt = b.crypto_aead_xchacha20poly1305_ietf_decrypt
NPUB = b.crypto_aead_xchacha20poly1305_ietf_NPUBBYTES
KEYBYTES = b.crypto_aead_xchacha20poly1305_ietf_KEYBYTES
return Construction(encrypt, decrypt, NPUB, KEYBYTES)
@pytest.mark.parametrize(
"kv",
chacha20poly1305_agl_vectors()
+ chacha20poly1305_ietf_vectors()
+ xchacha20poly1305_ietf_vectors(),
)
def test_chacha20poly1305_variants_kat(kv: Dict[str, bytes]):
msg = binascii.unhexlify(kv["IN"])
ad = binascii.unhexlify(kv["AD"])
nonce = binascii.unhexlify(kv["NONCE"])
k = binascii.unhexlify(kv["KEY"])
c = _getconstruction(kv["AEAD"])
_tag = kv.get("TAG", b"")
exp = binascii.unhexlify(kv["CT"]) + binascii.unhexlify(_tag)
out = c.encrypt(msg, ad, nonce, k)
assert out == exp
@given(
sampled_from(
(b"chacha20-poly1305-old", b"chacha20-poly1305", b"xchacha20-poly1305")
),
binary(min_size=0, max_size=100),
binary(min_size=0, max_size=50),
binary(
min_size=b.crypto_aead_xchacha20poly1305_ietf_NPUBBYTES,
max_size=b.crypto_aead_xchacha20poly1305_ietf_NPUBBYTES,
),
binary(
min_size=b.crypto_aead_chacha20poly1305_KEYBYTES,
max_size=b.crypto_aead_chacha20poly1305_KEYBYTES,
),
)
@settings(deadline=None, max_examples=20)
def test_chacha20poly1305_variants_roundtrip(
construction: bytes, message: bytes, aad: bytes, nonce: bytes, key: bytes
):
c = _getconstruction(construction)
unonce = nonce[: c.NPUB]
ct = c.encrypt(message, aad, unonce, key)
pt = c.decrypt(ct, aad, unonce, key)
assert pt == message
with pytest.raises(exc.CryptoError):
ct1 = bytearray(ct)
ct1[0] = ct1[0] ^ 0xFF
c.decrypt(ct1, aad, unonce, key)
@pytest.mark.parametrize(
"construction",
[b"chacha20-poly1305-old", b"chacha20-poly1305", b"xchacha20-poly1305"],
)
def test_chacha20poly1305_variants_wrong_params(construction: bytes):
c = _getconstruction(construction)
nonce = b"\x00" * c.NPUB
key = b"\x00" * c.KEYBYTES
aad = None
c.encrypt(b"", aad, nonce, key)
# The first two checks call encrypt with a nonce/key that's too short. Otherwise,
# the types are fine. (TODO: Should this raise ValueError rather than TypeError?
# Doing so would be a breaking change.)
with pytest.raises(exc.TypeError):
c.encrypt(b"", aad, nonce[:-1], key)
with pytest.raises(exc.TypeError):
c.encrypt(b"", aad, nonce, key[:-1])
# Type safety: mypy spots these next two errors, but we want to check that they're
# spotted at runtime too.
with pytest.raises(exc.TypeError):
c.encrypt(b"", aad, nonce.decode("utf-8"), key) # type: ignore[arg-type]
with pytest.raises(exc.TypeError):
c.encrypt(b"", aad, nonce, key.decode("utf-8")) # type: ignore[arg-type]
@pytest.mark.parametrize(
"construction",
[b"chacha20-poly1305-old", b"chacha20-poly1305", b"xchacha20-poly1305"],
)
def test_chacha20poly1305_variants_str_msg(construction: bytes):
c = _getconstruction(construction)
nonce = b"\x00" * c.NPUB
key = b"\x00" * c.KEYBYTES
aad = None
with pytest.raises(exc.TypeError):
c.encrypt("", aad, nonce, key) # type: ignore[arg-type]
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