tests/hazmat/primitives/test_asym_utils.py

# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.

from __future__ import absolute_import, division, print_function

import pytest

from cryptography.hazmat.primitives.asymmetric.utils import (
    Prehashed, decode_dss_signature, decode_rfc6979_signature,
    encode_dss_signature, encode_rfc6979_signature,
)
from cryptography.utils import CryptographyDeprecationWarning


def test_deprecated_rfc6979_signature():
    with pytest.warns(CryptographyDeprecationWarning):
        sig = encode_rfc6979_signature(1, 1)
    assert sig == b"0\x06\x02\x01\x01\x02\x01\x01"
    with pytest.warns(CryptographyDeprecationWarning):
        decoded = decode_rfc6979_signature(sig)
    assert decoded == (1, 1)


def test_dss_signature():
    sig = encode_dss_signature(1, 1)
    assert sig == b"0\x06\x02\x01\x01\x02\x01\x01"
    assert decode_dss_signature(sig) == (1, 1)

    r_s1 = (
        1037234182290683143945502320610861668562885151617,
        559776156650501990899426031439030258256861634312
    )
    sig2 = encode_dss_signature(*r_s1)
    assert sig2 == (
        b'0-\x02\x15\x00\xb5\xaf0xg\xfb\x8bT9\x00\x13\xccg\x02\r\xdf\x1f,\x0b'
        b'\x81\x02\x14b\r;"\xabP1D\x0c>5\xea\xb6\xf4\x81)\x8f\x9e\x9f\x08'
    )
    assert decode_dss_signature(sig2) == r_s1

    sig3 = encode_dss_signature(0, 0)
    assert sig3 == b"0\x06\x02\x01\x00\x02\x01\x00"
    assert decode_dss_signature(sig3) == (0, 0)

    sig4 = encode_dss_signature(-1, 0)
    assert sig4 == b"0\x06\x02\x01\xFF\x02\x01\x00"
    assert decode_dss_signature(sig4) == (-1, 0)


def test_encode_dss_non_integer():
    with pytest.raises(ValueError):
        encode_dss_signature("h", 3)

    with pytest.raises(ValueError):
        encode_dss_signature("3", "2")

    with pytest.raises(ValueError):
        encode_dss_signature(3, "h")

    with pytest.raises(ValueError):
        encode_dss_signature(3.3, 1.2)

    with pytest.raises(ValueError):
        encode_dss_signature("hello", "world")


def test_decode_dss_trailing_bytes():
    with pytest.raises(ValueError):
        decode_dss_signature(b"0\x06\x02\x01\x01\x02\x01\x01\x00\x00\x00")


def test_decode_dss_invalid_asn1():
    with pytest.raises(ValueError):
        # This byte sequence has an invalid ASN.1 sequence length as well as
        # an invalid integer length for the second integer.
        decode_dss_signature(b"0\x07\x02\x01\x01\x02\x02\x01")

    with pytest.raises(ValueError):
        # This is the BER "end-of-contents octets".
        decode_dss_signature(b"\x00\x00")


def test_pass_invalid_prehashed_arg():
    with pytest.raises(TypeError):
        Prehashed(object())