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authorDamir Jelić <poljar@termina.org.uk>2019-04-02 12:56:06 +0200
committerDamir Jelić <poljar@termina.org.uk>2019-04-02 12:56:59 +0200
commitfcfa5f12a4cd482973fdf03000af4a26a360dc2e (patch)
treee14fe09246b0eba099c331bee69c0edfdc71c646
parent446628753b6283f6dcbf27589b2c18f93c71768b (diff)
python: Expose the sha256() function in the utilities.
Signed-off-by: Damir Jelić <poljar@termina.org.uk>
-rw-r--r--python/olm/__init__.py2
-rw-r--r--python/olm/utility.py57
-rw-r--r--python/tests/utils_test.py29
3 files changed, 78 insertions, 10 deletions
diff --git a/python/olm/__init__.py b/python/olm/__init__.py
index fe3e199..9ac45b0 100644
--- a/python/olm/__init__.py
+++ b/python/olm/__init__.py
@@ -21,7 +21,7 @@ Olm Python bindings
| © Copyright 2015-2017 by OpenMarket Ltd
| © Copyright 2018 by Damir Jelić
"""
-from .utility import ed25519_verify, OlmVerifyError
+from .utility import ed25519_verify, OlmVerifyError, OlmHashError, sha256
from .account import Account, OlmAccountError
from .session import (
Session,
diff --git a/python/olm/utility.py b/python/olm/utility.py
index 121ff63..10d5ab4 100644
--- a/python/olm/utility.py
+++ b/python/olm/utility.py
@@ -32,6 +32,7 @@ Examples:
# pylint: disable=redefined-builtin,unused-import
from typing import AnyStr, Type
+from future.utils import bytes_to_native_str
# pylint: disable=no-name-in-module
from _libolm import ffi, lib # type: ignore
@@ -49,6 +50,10 @@ class OlmVerifyError(Exception):
"""libolm signature verification exception."""
+class OlmHashError(Exception):
+ """libolm hash calculation exception."""
+
+
class _Utility(object):
# pylint: disable=too-few-public-methods
"""libolm Utility class."""
@@ -64,12 +69,12 @@ class _Utility(object):
track_for_finalization(cls, cls._utility, _clear_utility)
@classmethod
- def _check_error(cls, ret):
- # type: (int) -> None
+ def _check_error(cls, ret, error_class):
+ # type: (int, Type) -> None
if ret != lib.olm_error():
return
- raise OlmVerifyError("{}".format(
+ raise error_class("{}".format(
ffi.string(lib.olm_utility_last_error(
cls._utility)).decode("utf-8")))
@@ -84,18 +89,41 @@ class _Utility(object):
byte_signature = to_bytearray(signature)
try:
- cls._check_error(
- lib.olm_ed25519_verify(cls._utility, byte_key, len(byte_key),
- ffi.from_buffer(byte_message),
- len(byte_message),
- ffi.from_buffer(byte_signature),
- len(byte_signature)))
+ ret = lib.olm_ed25519_verify(
+ cls._utility,
+ byte_key,
+ len(byte_key),
+ ffi.from_buffer(byte_message),
+ len(byte_message),
+ ffi.from_buffer(byte_signature),
+ len(byte_signature)
+ )
+
+ cls._check_error(ret, OlmVerifyError)
+
finally:
# clear out copies of the message, which may be a plaintext
if byte_message is not message:
for i in range(0, len(byte_message)):
byte_message[i] = 0
+ @classmethod
+ def _sha256(cls, input):
+ # type: (Type[_Utility], AnyStr) -> str
+ if not cls._utility:
+ cls._allocate()
+
+ byte_input = to_bytes(input)
+ hash_length = lib.olm_sha256_length(cls._utility)
+ hash = ffi.new("char[]", hash_length)
+
+ ret = lib.olm_sha256(cls._utility, byte_input, len(byte_input),
+ hash, hash_length)
+
+ cls._check_error(ret, OlmHashError)
+
+ return bytes_to_native_str(ffi.unpack(hash, hash_length))
+
def ed25519_verify(key, message, signature):
# type: (AnyStr, AnyStr, AnyStr) -> None
@@ -109,3 +137,14 @@ def ed25519_verify(key, message, signature):
signature(bytes): The message signature.
"""
return _Utility._ed25519_verify(key, message, signature)
+
+
+def sha256(input_string):
+ # type: (AnyStr) -> str
+ """Calculate the SHA-256 hash of the input and encodes it as base64.
+
+ Args:
+ input_string(str): The input for which the hash will be calculated.
+
+ """
+ return _Utility._sha256(input_string)
diff --git a/python/tests/utils_test.py b/python/tests/utils_test.py
new file mode 100644
index 0000000..a552d12
--- /dev/null
+++ b/python/tests/utils_test.py
@@ -0,0 +1,29 @@
+import base64
+import hashlib
+
+from future.utils import bytes_to_native_str
+from hypothesis import given
+from hypothesis.strategies import text
+
+from olm import sha256
+from olm._compat import to_bytes
+
+
+class TestClass(object):
+ @given(text(), text())
+ def test_sha256(self, input1, input2):
+ first_hash = sha256(input1)
+ second_hash = sha256(input2)
+
+ hashlib_hash = base64.b64encode(
+ hashlib.sha256(to_bytes(input1)).digest()
+ )
+
+ hashlib_hash = bytes_to_native_str(hashlib_hash[:-1])
+
+ if input1 == input2:
+ assert first_hash == second_hash
+ else:
+ assert first_hash != second_hash
+
+ assert hashlib_hash == first_hash