diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 258cc345dc..a5365c4fe4 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -863,8 +863,10 @@ class AuthHandler(BaseHandler):
         """
 
         def _do_validate_hash():
-            return bcrypt.hashpw(password.encode('utf8') + self.hs.config.password_pepper,
-                                 stored_hash.encode('utf8')) == stored_hash
+            return bcrypt.checkpw(
+                password.encode('utf8') + self.hs.config.password_pepper,
+                stored_hash.encode('utf8')
+            )
 
         if stored_hash:
             return make_deferred_yieldable(threads.deferToThread(_do_validate_hash))
diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py
index 5d65b5fd6e..91179ce532 100644
--- a/synapse/python_dependencies.py
+++ b/synapse/python_dependencies.py
@@ -31,7 +31,7 @@ REQUIREMENTS = {
     "pyyaml": ["yaml"],
     "pyasn1": ["pyasn1"],
     "daemonize": ["daemonize"],
-    "bcrypt": ["bcrypt"],
+    "bcrypt": ["bcrypt>=3.1.0"],
     "pillow": ["PIL"],
     "pydenticon": ["pydenticon"],
     "ujson": ["ujson"],