refactor!: remove md4 and related ENABLE_BLAKE2B_HASHING feature flag

.github/workflows/unit-tests.yml

@@ -71,29 +71,7 @@ jobs:
 
       - name: install system requirements
         run: |
-          sudo apt-get update && sudo apt-get install libmysqlclient-dev libxmlsec1-dev lynx openssl
-
-      # This is needed until the ENABLE_BLAKE2B_HASHING can be removed and we
-      # can stop using MD4 by default.
-      - name: enable md4 hashing in libssl
-        run: |
-          cat <<EOF | sudo tee /etc/ssl/openssl.cnf
-          # Use this in order to automatically load providers.
-          openssl_conf = openssl_init
-
-          [openssl_init]
-          providers = provider_sect
-
-          [provider_sect]
-          default = default_sect
-          legacy = legacy_sect
-
-          [default_sect]
-          activate = 1
-
-          [legacy_sect]
-          activate = 1
-          EOF
+          sudo apt-get update && sudo apt-get install libmysqlclient-dev libxmlsec1-dev lynx
 
       - name: Start MongoDB
         uses: supercharge/mongodb-github-action@1.11.0

cms/envs/common.py

@@ -566,9 +566,6 @@ FEATURES = {
     # .. toggle_tickets: https://github.com/openedx/edx-platform/pull/33911
     'ENABLE_GRADING_METHOD_IN_PROBLEMS': False,
 
-    # See annotations in lms/envs/common.py for details.
-    'ENABLE_BLAKE2B_HASHING': False,
-
     # .. toggle_name: FEATURES['BADGES_ENABLED']
     # .. toggle_implementation: DjangoSetting
     # .. toggle_default: False

common/djangoapps/util/memcache.py

@@ -7,7 +7,6 @@ so that we can cache any keys, not just ones that memcache would ordinarily acce
 import hashlib
 from urllib.parse import quote_plus
 
-from django.conf import settings
 from django.utils.encoding import smart_str
 
 
@@ -15,10 +14,7 @@ def fasthash(string):
     """
     Hashes `string` into a string representation of a 128-bit digest.
     """
-    if settings.FEATURES.get("ENABLE_BLAKE2B_HASHING", False):
-        hash_obj = hashlib.new("blake2b", digest_size=16)
-    else:
-        hash_obj = hashlib.new("md4")
+    hash_obj = hashlib.new("blake2b", digest_size=16)
     hash_obj.update(string.encode('utf-8'))
     return hash_obj.hexdigest()
 

common/djangoapps/util/tests/test_memcache.py

@@ -3,15 +3,11 @@ Tests for memcache in util app
 """
 
 
-from django.conf import settings
 from django.core.cache import caches
-from django.test import TestCase, override_settings
+from django.test import TestCase
 
 from common.djangoapps.util.memcache import safe_key
 
-BLAKE2B_ENABLED_FEATURES = settings.FEATURES.copy()
-BLAKE2B_ENABLED_FEATURES["ENABLE_BLAKE2B_HASHING"] = True
-
 
 class MemcacheTest(TestCase):
     """
@@ -55,20 +51,6 @@ class MemcacheTest(TestCase):
             # The key should now be valid
             assert self._is_valid_key(key), f'Failed for key length {length}'
 
-    @override_settings(FEATURES=BLAKE2B_ENABLED_FEATURES)
-    def test_safe_key_long_with_blake2b_enabled(self):
-        # Choose lengths close to memcached's cutoff (250)
-        for length in [248, 249, 250, 251, 252]:
-
-            # Generate a key of that length
-            key = 'a' * length
-
-            # Make the key safe
-            key = safe_key(key, '', '')
-
-            # The key should now be valid
-            assert self._is_valid_key(key), f'Failed for key length {length}'
-
     def test_long_key_prefix_version(self):
 
         # Long key
@@ -83,34 +65,6 @@ class MemcacheTest(TestCase):
         key = safe_key('key', 'prefix', 'a' * 300)
         assert self._is_valid_key(key)
 
-    @override_settings(FEATURES=BLAKE2B_ENABLED_FEATURES)
-    def test_long_key_prefix_version_with_blake2b_enabled(self):
-
-        # Long key
-        key = safe_key('a' * 300, 'prefix', 'version')
-        assert self._is_valid_key(key)
-
-        # Long prefix
-        key = safe_key('key', 'a' * 300, 'version')
-        assert self._is_valid_key(key)
-
-        # Long version
-        key = safe_key('key', 'prefix', 'a' * 300)
-        assert self._is_valid_key(key)
-
-    def test_safe_key_unicode(self):
-
-        for unicode_char in self.UNICODE_CHAR_CODES:
-
-            # Generate a key with that character
-            key = chr(unicode_char)
-
-            # Make the key safe
-            key = safe_key(key, '', '')
-
-            # The key should now be valid
-            assert self._is_valid_key(key), f'Failed for unicode character {unicode_char}'
-
     def test_safe_key_prefix_unicode(self):
 
         for unicode_char in self.UNICODE_CHAR_CODES:

lms/envs/common.py

@@ -1059,18 +1059,6 @@ FEATURES = {
     # .. toggle_creation_date: 2024-04-24
     'ENABLE_COURSEWARE_SEARCH_VERIFIED_ENROLLMENT_REQUIRED': False,
 
-    # .. toggle_name: FEATURES['ENABLE_BLAKE2B_HASHING']
-    # .. toggle_implementation: DjangoSetting
-    # .. toggle_default: False
-    # .. toggle_description: Enables the memcache to use the blake2b hash algorithm instead of depreciated md4 for keys
-    #   exceeding 250 characters
-    # .. toggle_use_cases: open_edx
-    # .. toggle_creation_date: 2024-04-02
-    # .. toggle_target_removal_date: 2024-12-09
-    # .. toggle_warning: For consistency, keep the value in sync with the setting of the same name in the LMS and CMS.
-    # .. toggle_tickets: https://github.com/openedx/edx-platform/pull/34442
-    'ENABLE_BLAKE2B_HASHING': False,
-
     # .. toggle_name: FEATURES['BADGES_ENABLED']
     # .. toggle_implementation: DjangoSetting
     # .. toggle_default: False