From 66c9cd928601725e27aa64255e56b3a7e481a08d Mon Sep 17 00:00:00 2001 From: David Reid Date: Mon, 20 Jan 2014 16:05:53 -0800 Subject: Refactor HKDF support and provide vectors for tests. --- cryptography/hazmat/primitives/kdf/hkdf.py | 52 ++++++++++++++ cryptography/hkdf.py | 43 ----------- tests/hazmat/primitives/test_hkdf_vectors.py | 50 +++++++++++++ tests/hazmat/primitives/utils.py | 31 ++++++++ .../primitives/vectors/KDF/rfc-5869-HKDF.txt | 83 ++++++++++++++++++++++ tests/test_utils.py | 57 ++++++++++++++- tests/utils.py | 44 ++++++++++++ 7 files changed, 315 insertions(+), 45 deletions(-) create mode 100644 cryptography/hazmat/primitives/kdf/hkdf.py delete mode 100644 cryptography/hkdf.py create mode 100644 tests/hazmat/primitives/test_hkdf_vectors.py create mode 100644 tests/hazmat/primitives/vectors/KDF/rfc-5869-HKDF.txt diff --git a/cryptography/hazmat/primitives/kdf/hkdf.py b/cryptography/hazmat/primitives/kdf/hkdf.py new file mode 100644 index 00000000..8d36c80b --- /dev/null +++ b/cryptography/hazmat/primitives/kdf/hkdf.py @@ -0,0 +1,52 @@ +# 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. + +from cryptography.hazmat.primitives import hmac +from cryptography.hazmat.primitives import hashes +from cryptography.hazmat.primitives import constant_time + +def hkdf_derive(input_key, key_length, salt, info, hash, backend): + if hash is None: + hash = hashes.SHA256() + + if info is None: + info = b"" + + if salt is None: + salt = b"\x00" * (hash.digest_size // 8) + + h = hmac.HMAC(salt, hash, backend=backend) + h.update(input_key) + PRK = h.finalize() + + output = [b''] + counter = 1 + + while (hash.digest_size // 8) * len(output) < key_length: + h = hmac.HMAC(PRK, hash, backend=backend) + h.update(output[-1]) + h.update(info) + h.update(chr(counter)) + output.append(h.finalize()) + counter += 1 + + return b"".join(output)[:key_length] + + +def hkdf_verify(expected, input_key, key_length, salt, info, hash, backend): + derived = hkdf_derive(input_key, key_length, salt=salt, info=info, + hash=hash, backend=backend) + + if not constant_time.bytes_eq(expected, derived): + raise ValueError("") + diff --git a/cryptography/hkdf.py b/cryptography/hkdf.py deleted file mode 100644 index 9665ce57..00000000 --- a/cryptography/hkdf.py +++ /dev/null @@ -1,43 +0,0 @@ -from cryptography.hazmat.backends import default_backend -from cryptography.hazmat.primitives import hmac -from cryptography.hazmat.primitives import hashes -from cryptography.hazmat.primitives import constant_time - -def hkdf_derive(input_key, key_length, salt=None, info=None, hash=None, backend=None): - if hash is None: - hash = hashes.SHA256() - - if backend is None: - backend = default_backend() - - if info is None: - info = b"" - - if salt is None: - salt = b"\x00" * (hash.digest_size // 8) - - h = hmac.HMAC(salt, hash, backend=backend) - h.update(input_key) - PRK = h.finalize() - - output = [b''] - counter = 1 - - while (hash.digest_size // 8) * len(output) < key_length: - h = hmac.HMAC(PRK, hash, backend=backend) - h.update(output[-1]) - h.update(info) - h.update(chr(counter)) - output.append(h.finalize()) - counter += 1 - - return b"".join(output)[:key_length] - - -def hkdf_verify(expected, input_key, key_length, salt=None, info=None, - hash=None, backend=None): - derived = hkdf_derive(input_key, key_length, salt=salt, info=info, - hash=hash, backend=backend) - - return constant_time.bytes_eq(expected, derived) - diff --git a/tests/hazmat/primitives/test_hkdf_vectors.py b/tests/hazmat/primitives/test_hkdf_vectors.py new file mode 100644 index 00000000..2595c956 --- /dev/null +++ b/tests/hazmat/primitives/test_hkdf_vectors.py @@ -0,0 +1,50 @@ +# 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. + +from __future__ import absolute_import, division, print_function + +import os + +import pytest + +from cryptography.hazmat.primitives import hashes + +from .utils import generate_hkdf_test +from ...utils import load_hkdf_vectors + +@pytest.mark.supported( + only_if=lambda backend: backend.hash_supported(hashes.SHA1()), + skip_message="Does not support SHA1." +) +@pytest.mark.hash +class TestHKDFSHA1(object): + test_HKDFSHA1 = generate_hkdf_test( + load_hkdf_vectors, + os.path.join("kdf"), + ["rfc-5869-HKDF-SHA1.txt"], + hashes.SHA1() + ) + + +@pytest.mark.supported( + only_if=lambda backend: backend.hash_supported(hashes.SHA256()), + skip_message="Does not support SHA256." +) +@pytest.mark.hash +class TestHKDFSHA256(object): + test_HKDFSHA1 = generate_hkdf_test( + load_hkdf_vectors, + os.path.join("kdf"), + ["rfc-5869-HKDF-SHA256.txt"], + hashes.SHA256() + ) diff --git a/tests/hazmat/primitives/utils.py b/tests/hazmat/primitives/utils.py index 6b1d055d..e546fa79 100644 --- a/tests/hazmat/primitives/utils.py +++ b/tests/hazmat/primitives/utils.py @@ -6,6 +6,8 @@ import pytest from cryptography.hazmat.primitives import hashes, hmac from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC from cryptography.hazmat.primitives.ciphers import Cipher +from cryptography.hazmat.primitives.kdf.hkdf import hkdf_derive + from cryptography.exceptions import ( AlreadyFinalized, NotYetFinalized, AlreadyUpdated, InvalidTag, ) @@ -297,3 +299,32 @@ def aead_tag_exception_test(backend, cipher_factory, mode_factory): ) with pytest.raises(ValueError): cipher.encryptor() + + +def hkdf_test(backend, algorithm, params): + ikm = params[0] + salt = params[1] + info = params[2] + length = params[3] + expected_okm = params[4] + + okm = hkdf_derive( + binascii.unhexlify(ikm), + length, + binascii.unhexlify(salt), + binascii.unhexlify(info), + algorithm, + backend=backend + ) + + assert binascii.hexlify(okm) == expected_okm + + +def generate_hkdf_test(param_loader, path, file_names, algorithm): + all_params = _load_all_params(path, file_names, param_loader) + + @pytest.mark.parametrize("params", all_params) + def test_hkdf(self, backend, params): + hkdf_test(backend, algorithm, params) + + return test_hkdf diff --git a/tests/hazmat/primitives/vectors/KDF/rfc-5869-HKDF.txt b/tests/hazmat/primitives/vectors/KDF/rfc-5869-HKDF.txt new file mode 100644 index 00000000..885a5266 --- /dev/null +++ b/tests/hazmat/primitives/vectors/KDF/rfc-5869-HKDF.txt @@ -0,0 +1,83 @@ +# A.1. Test Case 1 +# Basic test case with SHA-256 + +Hash = SHA-256 +IKM = 0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b +salt = 000102030405060708090a0b0c +info = f0f1f2f3f4f5f6f7f8f9 +L = 42 +PRK = 077709362c2e32df0ddc3f0dc47bba6390b6c73bb50f9c3122ec844ad7c2b3e5 +OKM = 3cb25f25faacd57a90434f64d0362f2a2d2d0a90cf1a5a4c5db02d56ecc4c5bf34007208d5b887185865 + +# A.2. Test Case 2 +# Test with SHA-256 and longer inputs/outputs + +Hash = SHA-256 +IKM = 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f303132333435363738393a3b3c3d3e3f404142434445464748494a4b4c4d4e4f +salt = 606162636465666768696a6b6c6d6e6f707172737475767778797a7b7c7d7e7f808182838485868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9fa0a1a2a3a4a5a6a7a8a9aaabacadaeaf +info = b0b1b2b3b4b5b6b7b8b9babbbcbdbebfc0c1c2c3c4c5c6c7c8c9cacbcccdcecfd0d1d2d3d4d5d6d7d8d9dadbdcdddedfe0e1e2e3e4e5e6e7e8e9eaebecedeeeff0f1f2f3f4f5f6f7f8f9fafbfcfdfeff +L = 82 + +PRK = 06a6b88c5853361a06104c9ceb35b45cef760014904671014a193f40c15fc244 +OKM = b11e398dc80327a1c8e7f78c596a49344f012eda2d4efad8a050cc4c19afa97c59045a99cac7827271cb41c65e590e09da3275600c2f09b8367793a9aca3db71cc30c58179ec3e87c14c01d5c1f3434f1d87 + +# A.3. Test Case 3 +# Test with SHA-256 and zero-length salt/info + +Hash = SHA-256 +IKM = 0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b +salt = +info = +L = 42 + +PRK = 19ef24a32c717b167f33a91d6f648bdf96596776afdb6377ac434c1c293ccb04 +OKM = 8da4e775a563c18f715f802a063c5a31b8a11f5c5ee1879ec3454e5f3c738d2d9d201395faa4b61a96c8 + +# A.4. Test Case 4 +# Basic test case with SHA-1 + +Hash = SHA-1 +IKM = 0b0b0b0b0b0b0b0b0b0b0b +salt = 000102030405060708090a0b0c +info = f0f1f2f3f4f5f6f7f8f9 +L = 42 + +PRK = 9b6c18c432a7bf8f0e71c8eb88f4b30baa2ba243 +OKM = 085a01ea1b10f36933068b56efa5ad81a4f14b822f5b091568a9cdd4f155fda2c22e422478d305f3f896 + +# A.5. Test Case 5 +# Test with SHA-1 and longer inputs/outputs + +Hash = SHA-1 +IKM = 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f303132333435363738393a3b3c3d3e3f404142434445464748494a4b4c4d4e4f +salt = 606162636465666768696a6b6c6d6e6f707172737475767778797a7b7c7d7e7f808182838485868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9fa0a1a2a3a4a5a6a7a8a9aaabacadaeaf +info = b0b1b2b3b4b5b6b7b8b9babbbcbdbebfc0c1c2c3c4c5c6c7c8c9cacbcccdcecfd0d1d2d3d4d5d6d7d8d9dadbdcdddedfe0e1e2e3e4e5e6e7e8e9eaebecedeeeff0f1f2f3f4f5f6f7f8f9fafbfcfdfeff +L = 82 + +PRK = 8adae09a2a307059478d309b26c4115a224cfaf6 +OKM = 0bd770a74d1160f7c9f12cd5912a06ebff6adcae899d92191fe4305673ba2ffe8fa3f1a4e5ad79f3f334b3b202b2173c486ea37ce3d397ed034c7f9dfeb15c5e927336d0441f4c4300e2cff0d0900b52d3b4 + +# A.6. Test Case 6 +# Test with SHA-1 and zero-length salt/info + +Hash = SHA-1 +IKM = 0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b +salt = +info = +L = 42 + +PRK = da8c8a73c7fa77288ec6f5e7c297786aa0d32d01 +OKM = 0ac1af7002b3d761d1e55298da9d0506b9ae52057220a306e07b6b87e8df21d0ea00033de03984d34918 + +# A.7. Test Case 7 +# Test with SHA-1, salt not provided (defaults to HashLen zero octets), +# zero-length info + +Hash = SHA-1 +IKM = 0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c +salt = not provided (defaults to HashLen zero octets) +info = +L = 42 + +PRK = 2adccada18779e7c2077ad2eb19d3f3e731385dd +OKM = 2c91117204d745f3500d636a62f64f0ab3bae548aa53d423b0d1f27ebba6f5e5673a081d70cce7acfc diff --git a/tests/test_utils.py b/tests/test_utils.py index 8ecb33f9..3bc4bf65 100644 --- a/tests/test_utils.py +++ b/tests/test_utils.py @@ -20,8 +20,8 @@ import pytest from .utils import ( load_nist_vectors, load_vectors_from_file, load_cryptrec_vectors, - load_openssl_vectors, load_hash_vectors, check_for_iface, - check_backend_support, select_backends + load_openssl_vectors, load_hash_vectors, load_hkdf_vectors, + check_for_iface, check_backend_support, select_backends ) @@ -529,3 +529,56 @@ def test_load_nist_gcm_vectors(): 'ct': b'15c4db4cbb451211179d57017f', 'fail': True}, ] + + +def test_load_hkdf_vectors(): + vector_data = textwrap.dedent(""" + # A.1. Test Case 1 + # Basic test case with SHA-256 + + Hash = SHA-256 + IKM = 0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b + salt = 000102030405060708090a0b0c + info = f0f1f2f3f4f5f6f7f8f9 + L = 42 + """ + "PRK = 077709362c2e32df0ddc3f0dc47bba6390b6c73bb50f9c3122ec844ad7c2" + "b3e5\n" + "OKM = 3cb25f25faacd57a90434f64d0362f2a2d2d0a90cf1a5a4c5db02d56ecc4" + "c5bf34007208d5b887185865\n" + """ + # A.2. Test Case 2 + # Test with SHA-256 and longer inputs/outputs + + Hash = SHA-256 + """ + "IKM = 000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d" + "1e1f202122232425262728292a2b2c2d2e2f303132333435363738393a3b3c3d3e3" + "f404142434445464748494a4b4c4d4e4f\n" + "salt = \n" + "info = \n" + "L = 82\n" + "PRK = 06a6b88c5853361a06104c9ceb35b45cef760014904671014a193f40c15f" + "c244\n" + "OKM = b11e398dc80327a1c8e7f78c596a49344f012eda2d4efad8a050cc4c19af" + "a97c59045a99cac7827271cb41c65e590e09da3275600c2f09b8367793a9aca3db7" + "1cc30c58179ec3e87c14c01d5c1f3434f1d87\n" + ).splitlines() + + assert load_hkdf_vectors(vector_data) == [ + (b"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b", + b"000102030405060708090a0b0c", + b"f0f1f2f3f4f5f6f7f8f9", + 42, + b"3cb25f25faacd57a90434f64d0362f2a2d2d0a90cf1a5a4c5db02d56ecc4c5bf34" + b"007208d5b887185865"), + (b"000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f20" + b"2122232425262728292a2b2c2d2e2f303132333435363738393a3b3c3d3e3f4041" + b"42434445464748494a4b4c4d4e4f", + b"", + b"", + 82, + b"b11e398dc80327a1c8e7f78c596a49344f012eda2d4efad8a050cc4c19afa97c59" + b"045a99cac7827271cb41c65e590e09da3275600c2f09b8367793a9aca3db71cc30" + b"c58179ec3e87c14c01d5c1f3434f1d87") + ] diff --git a/tests/utils.py b/tests/utils.py index 5c0e524f..5f2c6ff6 100644 --- a/tests/utils.py +++ b/tests/utils.py @@ -191,3 +191,47 @@ def load_hash_vectors(vector_data): else: raise ValueError("Unknown line in hash vector") return vectors + + +def load_hkdf_vectors(vector_data): + vectors = [] + + ikm = None + salt = None + info = None + length = None + okm = None + + for line in vector_data: + line = line.strip() + + if not line or line.startswith("#"): + continue + + elif line.startswith("IKM"): + ikm = line.split(" = ")[1].encode("ascii") + elif line.startswith("salt"): + l = line.split(" =") + if len(l) == 1: + salt = b"" + else: + salt = l[1].strip().encode("ascii") + elif line.startswith("info"): + l = line.split(" =") + if len(l) == 1: + info = b"" + else: + info = l[1].strip().encode("ascii") + elif line.startswith("L"): + length = int(line.split(" = ")[1]) + elif line.startswith("OKM"): + okm = line.split(" = ")[1].encode("ascii") + + vectors.append((ikm, salt, info, length, okm)) + ikm = None + salt = None + info = None + length = None + okm = None + + return vectors -- cgit v1.2.3