17.12

venv/lib/python3.7/site-packages/cryptography/hazmat/primitives/kdf/hkdf.py

@@ -0,0 +1,110 @@
+# 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 six
+
+from cryptography import utils
+from cryptography.exceptions import (
+    AlreadyFinalized, InvalidKey, UnsupportedAlgorithm, _Reasons
+)
+from cryptography.hazmat.backends.interfaces import HMACBackend
+from cryptography.hazmat.primitives import constant_time, hmac
+from cryptography.hazmat.primitives.kdf import KeyDerivationFunction
+
+
+@utils.register_interface(KeyDerivationFunction)
+class HKDF(object):
+    def __init__(self, algorithm, length, salt, info, backend):
+        if not isinstance(backend, HMACBackend):
+            raise UnsupportedAlgorithm(
+                "Backend object does not implement HMACBackend.",
+                _Reasons.BACKEND_MISSING_INTERFACE
+            )
+
+        self._algorithm = algorithm
+
+        if salt is None:
+            salt = b"\x00" * self._algorithm.digest_size
+        else:
+            utils._check_bytes("salt", salt)
+
+        self._salt = salt
+
+        self._backend = backend
+
+        self._hkdf_expand = HKDFExpand(self._algorithm, length, info, backend)
+
+    def _extract(self, key_material):
+        h = hmac.HMAC(self._salt, self._algorithm, backend=self._backend)
+        h.update(key_material)
+        return h.finalize()
+
+    def derive(self, key_material):
+        utils._check_byteslike("key_material", key_material)
+        return self._hkdf_expand.derive(self._extract(key_material))
+
+    def verify(self, key_material, expected_key):
+        if not constant_time.bytes_eq(self.derive(key_material), expected_key):
+            raise InvalidKey
+
+
+@utils.register_interface(KeyDerivationFunction)
+class HKDFExpand(object):
+    def __init__(self, algorithm, length, info, backend):
+        if not isinstance(backend, HMACBackend):
+            raise UnsupportedAlgorithm(
+                "Backend object does not implement HMACBackend.",
+                _Reasons.BACKEND_MISSING_INTERFACE
+            )
+
+        self._algorithm = algorithm
+
+        self._backend = backend
+
+        max_length = 255 * algorithm.digest_size
+
+        if length > max_length:
+            raise ValueError(
+                "Can not derive keys larger than {} octets.".format(
+                    max_length
+                ))
+
+        self._length = length
+
+        if info is None:
+            info = b""
+        else:
+            utils._check_bytes("info", info)
+
+        self._info = info
+
+        self._used = False
+
+    def _expand(self, key_material):
+        output = [b""]
+        counter = 1
+
+        while self._algorithm.digest_size * (len(output) - 1) < self._length:
+            h = hmac.HMAC(key_material, self._algorithm, backend=self._backend)
+            h.update(output[-1])
+            h.update(self._info)
+            h.update(six.int2byte(counter))
+            output.append(h.finalize())
+            counter += 1
+
+        return b"".join(output)[:self._length]
+
+    def derive(self, key_material):
+        utils._check_byteslike("key_material", key_material)
+        if self._used:
+            raise AlreadyFinalized
+
+        self._used = True
+        return self._expand(key_material)
+
+    def verify(self, key_material, expected_key):
+        if not constant_time.bytes_eq(self.derive(key_material), expected_key):
+            raise InvalidKey

venv/lib/python3.7/site-packages/cryptography/hazmat/primitives/kdf/scrypt.py

@@ -0,0 +1,63 @@
+# 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 sys
+
+from cryptography import utils
+from cryptography.exceptions import (
+    AlreadyFinalized, InvalidKey, UnsupportedAlgorithm, _Reasons
+)
+from cryptography.hazmat.backends.interfaces import ScryptBackend
+from cryptography.hazmat.primitives import constant_time
+from cryptography.hazmat.primitives.kdf import KeyDerivationFunction
+
+
+# This is used by the scrypt tests to skip tests that require more memory
+# than the MEM_LIMIT
+_MEM_LIMIT = sys.maxsize // 2
+
+
+@utils.register_interface(KeyDerivationFunction)
+class Scrypt(object):
+    def __init__(self, salt, length, n, r, p, backend):
+        if not isinstance(backend, ScryptBackend):
+            raise UnsupportedAlgorithm(
+                "Backend object does not implement ScryptBackend.",
+                _Reasons.BACKEND_MISSING_INTERFACE
+            )
+
+        self._length = length
+        utils._check_bytes("salt", salt)
+        if n < 2 or (n & (n - 1)) != 0:
+            raise ValueError("n must be greater than 1 and be a power of 2.")
+
+        if r < 1:
+            raise ValueError("r must be greater than or equal to 1.")
+
+        if p < 1:
+            raise ValueError("p must be greater than or equal to 1.")
+
+        self._used = False
+        self._salt = salt
+        self._n = n
+        self._r = r
+        self._p = p
+        self._backend = backend
+
+    def derive(self, key_material):
+        if self._used:
+            raise AlreadyFinalized("Scrypt instances can only be used once.")
+        self._used = True
+
+        utils._check_byteslike("key_material", key_material)
+        return self._backend.derive_scrypt(
+            key_material, self._salt, self._length, self._n, self._r, self._p
+        )
+
+    def verify(self, key_material, expected_key):
+        derived_key = self.derive(key_material)
+        if not constant_time.bytes_eq(derived_key, expected_key):
+            raise InvalidKey("Keys do not match.")

venv/lib/python3.7/site-packages/cryptography/hazmat/primitives/kdf/x963kdf.py

@@ -0,0 +1,68 @@
+# 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 struct
+
+from cryptography import utils
+from cryptography.exceptions import (
+    AlreadyFinalized, InvalidKey, UnsupportedAlgorithm, _Reasons
+)
+from cryptography.hazmat.backends.interfaces import HashBackend
+from cryptography.hazmat.primitives import constant_time, hashes
+from cryptography.hazmat.primitives.kdf import KeyDerivationFunction
+
+
+def _int_to_u32be(n):
+    return struct.pack('>I', n)
+
+
+@utils.register_interface(KeyDerivationFunction)
+class X963KDF(object):
+    def __init__(self, algorithm, length, sharedinfo, backend):
+
+        max_len = algorithm.digest_size * (2 ** 32 - 1)
+        if length > max_len:
+            raise ValueError(
+                "Can not derive keys larger than {} bits.".format(max_len))
+        if sharedinfo is not None:
+            utils._check_bytes("sharedinfo", sharedinfo)
+
+        self._algorithm = algorithm
+        self._length = length
+        self._sharedinfo = sharedinfo
+
+        if not isinstance(backend, HashBackend):
+            raise UnsupportedAlgorithm(
+                "Backend object does not implement HashBackend.",
+                _Reasons.BACKEND_MISSING_INTERFACE
+            )
+        self._backend = backend
+        self._used = False
+
+    def derive(self, key_material):
+        if self._used:
+            raise AlreadyFinalized
+        self._used = True
+        utils._check_byteslike("key_material", key_material)
+        output = [b""]
+        outlen = 0
+        counter = 1
+
+        while self._length > outlen:
+            h = hashes.Hash(self._algorithm, self._backend)
+            h.update(key_material)
+            h.update(_int_to_u32be(counter))
+            if self._sharedinfo is not None:
+                h.update(self._sharedinfo)
+            output.append(h.finalize())
+            outlen += len(output[-1])
+            counter += 1
+
+        return b"".join(output)[:self._length]
+
+    def verify(self, key_material, expected_key):
+        if not constant_time.bytes_eq(self.derive(key_material), expected_key):
+            raise InvalidKey