refactor: Simplify random integer generation

pyproject.toml

@@ -121,6 +121,7 @@ ignore = [
   "RUF001", # AmbiguousUnicodeCharacterString
   "S101",   # Use of `assert` detected
   "S110", # `try`-`except`-`pass` detected, consider logging the exception
+  "S311", # Standard pseudo-random generators are not suitable for cryptographic purposes
   "SIM108", # Use ternary operator
   "SIM110", # Use any()` instead of `for` loop
   "SIM118", # Don’t use .keys()

src/omemo_dr/session_manager.py

@@ -71,11 +71,11 @@ class OMEMOSessionManager(Observable):
 
     def _generate_keys(self) -> int:
         identity_key_pair = KeyHelper.generate_identity_key_pair()
-        our_device_id = KeyHelper.get_random_sequence(2147483647)
+        our_device_id = KeyHelper.get_random_int()
         self._storage.set_our_identity(our_device_id, identity_key_pair)
 
         signed_pre_key = KeyHelper.generate_signed_pre_key(
-            identity_key_pair, KeyHelper.get_random_sequence(65536)
+            identity_key_pair, KeyHelper.get_random_int()
         )
         self._storage.store_signed_pre_key(signed_pre_key.get_id(), signed_pre_key)
 

src/omemo_dr/util/keyhelper.py

 from __future__ import annotations
 
-import binascii
-import math
-import os
+import random
 import time
 
 from ..ecc.curve import Curve
@@ -27,20 +25,8 @@ class KeyHelper:
         return identity_key_pair
 
     @staticmethod
-    def generate_device_id() -> int:
-        """
-        Generate a registration ID.  Clients should only do this once,
-        at install time.
-        """
-        regId = KeyHelper.get_random_sequence()
-        return regId
-
-    @staticmethod
-    def get_random_sequence(max: int = 4294967296) -> int:
-        size = int(math.log(max) / math.log(2)) / 8
-        rand = os.urandom(int(size))
-        randh = binascii.hexlify(rand)
-        return int(randh, 16)
+    def get_random_int() -> int:
+        return random.randint(1, 2**31 - 1)
 
     @staticmethod
     def generate_pre_keys(start: int, count: int) -> list[PreKeyRecord]:

tests/inmemoryidentitykeystore.py

@@ -14,7 +14,7 @@ class InMemoryIdentityKeyStore:
             IdentityKey(identity_key_pair_keys.get_public_key()),
             identity_key_pair_keys.get_private_key(),
         )
-        self.our_device_id = KeyHelper.generate_device_id()
+        self.our_device_id = KeyHelper.get_random_int()
 
     def get_identity_key_pair(self) -> IdentityKeyPair:
         return self.identity_key_pair