python/tink/signature/_signature_key_manager_test.py

# Copyright 2019 Google LLC
#
# 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.
"""Tests for tink.python.tink._signature_key_manager."""

from __future__ import absolute_import
from __future__ import division
# Placeholder for import for type annotations
from __future__ import print_function

from absl.testing import absltest

from tink.proto import common_pb2
from tink.proto import ecdsa_pb2
from tink.proto import tink_pb2
from tink import core
from tink import signature


def setUpModule():
  signature.register()


def _sign_key_manager() -> core.PrivateKeyManager:
  key_manager = core.Registry.key_manager(
      'type.googleapis.com/google.crypto.tink.EcdsaPrivateKey')
  if not isinstance(key_manager, core.PrivateKeyManager):
    raise core.TinkError('key_manager is not a PrivateKeyManager')
  return key_manager


def _verify_key_manager() -> core.KeyManager:
  return core.Registry.key_manager(
      'type.googleapis.com/google.crypto.tink.EcdsaPublicKey')


def new_ecdsa_key_template(hash_type, curve_type, encoding, public=True):
  params = ecdsa_pb2.EcdsaParams(
      hash_type=hash_type, curve=curve_type, encoding=encoding)
  key_format = ecdsa_pb2.EcdsaKeyFormat(params=params)
  key_template = tink_pb2.KeyTemplate()
  if public:
    append = 'EcdsaPublicKey'
  else:
    append = 'EcdsaPrivateKey'
  key_template.type_url = 'type.googleapis.com/google.crypto.tink.' + append
  key_template.value = key_format.SerializeToString()
  return key_template


class PublicKeySignKeyManagerTest(absltest.TestCase):

  def setUp(self):
    super(PublicKeySignKeyManagerTest, self).setUp()
    self.key_manager_sign = _sign_key_manager()
    self.key_manager_verify = _verify_key_manager()

  def test_primitive_class(self):
    self.assertEqual(self.key_manager_sign.primitive_class(),
                     signature.PublicKeySign)
    self.assertEqual(self.key_manager_verify.primitive_class(),
                     signature.PublicKeyVerify)

  def test_key_type(self):
    self.assertEqual(self.key_manager_sign.key_type(),
                     'type.googleapis.com/google.crypto.tink.EcdsaPrivateKey')
    self.assertEqual(self.key_manager_verify.key_type(),
                     'type.googleapis.com/google.crypto.tink.EcdsaPublicKey')

  def test_new_key_data(self):
    key_template = new_ecdsa_key_template(
        common_pb2.SHA256, common_pb2.NIST_P256, ecdsa_pb2.DER, public=False)
    key_data = self.key_manager_sign.new_key_data(key_template)
    self.assertEqual(key_data.type_url, self.key_manager_sign.key_type())
    key = ecdsa_pb2.EcdsaPrivateKey()
    key.ParseFromString(key_data.value)
    public_key = key.public_key
    self.assertEqual(key.version, 0)
    self.assertEqual(public_key.version, 0)
    self.assertEqual(public_key.params.hash_type, common_pb2.SHA256)
    self.assertEqual(public_key.params.curve, common_pb2.NIST_P256)
    self.assertEqual(public_key.params.encoding, ecdsa_pb2.DER)
    self.assertLen(key.key_value, 32)

  def test_new_public_key_data_fails(self):
    key_template = new_ecdsa_key_template(
        common_pb2.SHA256, common_pb2.NIST_P256, ecdsa_pb2.DER, public=True)
    with self.assertRaises(core.TinkError):
      self.key_manager_verify.new_key_data(key_template)

  def test_sign_verify_success(self):
    priv_key = self.key_manager_sign.new_key_data(
        new_ecdsa_key_template(
            common_pb2.SHA256,
            common_pb2.NIST_P256,
            ecdsa_pb2.DER,
            public=False))
    pub_key = self.key_manager_sign.public_key_data(priv_key)

    verifier = self.key_manager_verify.primitive(pub_key)
    signer = self.key_manager_sign.primitive(priv_key)

    data = b'data'
    data_signature = signer.sign(data)

    # Starts with a DER sequence
    self.assertEqual(bytearray(data_signature)[0], 0x30)

    verifier.verify(data_signature, data)

  def test_verify_wrong(self):
    key_template = new_ecdsa_key_template(
        common_pb2.SHA256, common_pb2.NIST_P256, ecdsa_pb2.DER, public=False)
    priv_key = self.key_manager_sign.new_key_data(key_template)
    pub_key = self.key_manager_sign.public_key_data(priv_key)

    signer = self.key_manager_sign.primitive(priv_key)
    verifier = self.key_manager_verify.primitive(pub_key)

    data = b'data'
    with self.assertRaises(core.TinkError):
      verifier.verify(signer.sign(data), b'wrongdata')

    with self.assertRaises(core.TinkError):
      verifier.verify(b'wrongsignature', data)


if __name__ == '__main__':
  absltest.main()