repo_description: pure-python ECDSA signature/verification and ECDH key agreement
repo_topics: cryptography digital-signatures ecdh ecdsa elliptic-curves python
code: try:
      import unittest2 as unittest
  except ImportError:
      import unittest
  import pytest
  
  try:
      from gmpy2 import mpz
  
      GMPY = True
  except ImportError:  # pragma: no cover
      try:
          from gmpy import mpz
  
          GMPY = True
      except ImportError:
          GMPY = False
  
  from ._sha3 import shake_256
  from ._compat import bytes_to_int, int_to_bytes
  
  B2I_VECTORS = [
      (b"\x00\x01", "big", 1),
      (b"\x00\x01", "little", 0x0100),
      (b"", "big", 0),
      (b"\x00", "little", 0),
  ]
  
  
  @pytest.mark.parametrize("bytes_in,endian,int_out", B2I_VECTORS)
  def test_bytes_to_int(bytes_in, endian, int_out):
      out = bytes_to_int(bytes_in, endian)
      assert out == int_out
  
  
  class TestBytesToInt(unittest.TestCase):
      def test_bytes_to_int_wrong_endian(self):
          with self.assertRaises(ValueError):
              bytes_to_int(b"\x00", "middle")
  
      def test_int_to_bytes_wrong_endian(self):
          with self.assertRaises(ValueError):
              int_to_bytes(0, byteorder="middle")
  
  
  @pytest.mark.skipif(GMPY == False, reason="requires gmpy or gmpy2")
  def test_int_to_bytes_with_gmpy():
      assert int_to_bytes(mpz(1)) == b"\x01"
  
  
  I2B_VECTORS = [
      (0, None, "big", b""),
      (0, 1, "big", b"\x00"),
      (1, None, "big", b"\x01"),
      (0x0100, None, "little", b"\x00\x01"),
      (0x0100, 4, "little", b"\x00\x01\x00\x00"),
      (1, 4, "big", b"\x00\x00\x00\x01"),
  ]
  
  
  @pytest.mark.parametrize("int_in,length,endian,bytes_out", I2B_VECTORS)
  def test_int_to_bytes(int_in, length, endian, bytes_out):
      out = int_to_bytes(int_in, length, endian)
      assert out == bytes_out
  
  
  SHAKE_256_VECTORS = [
      (
          b"Message.",
          32,
          b"\x78\xa1\x37\xbb\x33\xae\xe2\x72\xb1\x02\x4f\x39\x43\xe5\xcf\x0c"
          b"\x4e\x9c\x72\x76\x2e\x34\x4c\xf8\xf9\xc3\x25\x9d\x4f\x91\x2c\x3a",
      ),
      (
          b"",
          32,
          b"\x46\xb9\xdd\x2b\x0b\xa8\x8d\x13\x23\x3b\x3f\xeb\x74\x3e\xeb\x24"
          b"\x3f\xcd\x52\xea\x62\xb8\x1b\x82\xb5\x0c\x27\x64\x6e\xd5\x76\x2f",
      ),
      (
          b"message",
          32,
          b"\x86\x16\xe1\xe4\xcf\xd8\xb5\xf7\xd9\x2d\x43\xd8\x6e\x1b\x14\x51"
          b"\xa2\xa6\x5a\xf8\x64\xfc\xb1\x26\xc2\x66\x0a\xb3\x46\x51\xb1\x75",
      ),
      (
          b"message",
          16,
          b"\x86\x16\xe1\xe4\xcf\xd8\xb5\xf7\xd9\x2d\x43\xd8\x6e\x1b\x14\x51",
      ),
      (
          b"message",
          64,
          b"\x86\x16\xe1\xe4\xcf\xd8\xb5\xf7\xd9\x2d\x43\xd8\x6e\x1b\x14\x51"
          b"\xa2\xa6\x5a\xf8\x64\xfc\xb1\x26\xc2\x66\x0a\xb3\x46\x51\xb1\x75"
          b"\x30\xd6\xba\x2a\x46\x65\xf1\x9d\xf0\x62\x25\xb1\x26\xd1\x3e\xed"
          b"\x91\xd5\x0d\xe7\xb9\xcb\x65\xf3\x3a\x46\xae\xd3\x6c\x7d\xc5\xe8",
      ),
      (
          b"A" * 1024,
          32,
          b"\xa5\xef\x7e\x30\x8b\xe8\x33\x64\xe5\x9c\xf3\xb5\xf3\xba\x20\xa3"
          b"\x5a\xe7\x30\xfd\xbc\x33\x11\xbf\x83\x89\x50\x82\xb4\x41\xe9\xb3",
      ),
  ]
  
  
  @pytest.mark.parametrize("msg,olen,ohash", SHAKE_256_VECTORS)
  def test_shake_256(msg, olen, ohash):
      out = shake_256(msg, olen)
      assert out == bytearray(ohash)
  