diff --git a/pungi/phases/createiso.py b/pungi/phases/createiso.py
index ec653ad6..57cde7d9 100644
--- a/pungi/phases/createiso.py
+++ b/pungi/phases/createiso.py
@@ -189,6 +189,14 @@ class CreateisoPhase(PhaseLoggerMixin, PhaseBase):
         if not old_config:
             self.logger.info("%s - no config for old compose", log_msg)
             return False
+
+        # Disable reuse if unsigned packages are allowed. The older compose
+        # could have unsigned packages, and those may have been signed since
+        # then. We want to regenerate the ISO to have signatures.
+        if None in self.compose.conf["sigkeys"]:
+            self.logger.info("%s - unsigned packages are allowed", log_msg)
+            return False
+
         # Convert current configuration to JSON and back to encode it similarly
         # to the old one
         config = json.loads(json.dumps(self.compose.conf))
diff --git a/pungi/phases/extra_isos.py b/pungi/phases/extra_isos.py
index da396d2b..1948a1c4 100644
--- a/pungi/phases/extra_isos.py
+++ b/pungi/phases/extra_isos.py
@@ -205,6 +205,14 @@ class ExtraIsosThread(WorkerThread):
         if not old_config:
             self.pool.log_info("%s - no config for old compose", log_msg)
             return False
+
+        # Disable reuse if unsigned packages are allowed. The older compose
+        # could have unsigned packages, and those may have been signed since
+        # then. We want to regenerate the ISO to have signatures.
+        if None in compose.conf["sigkeys"]:
+            self.pool.log_info("%s - unsigned packages are allowed", log_msg)
+            return False
+
         # Convert current configuration to JSON and back to encode it similarly
         # to the old one
         config = json.loads(json.dumps(compose.conf))
diff --git a/tests/test_createiso_phase.py b/tests/test_createiso_phase.py
index bb9b6892..e3e8793c 100644
--- a/tests/test_createiso_phase.py
+++ b/tests/test_createiso_phase.py
@@ -1390,7 +1390,9 @@ class CreateisoTryReusePhaseTest(helpers.PungiTestCase):
         )
 
     def test_old_config_changed(self):
-        compose = helpers.DummyCompose(self.topdir, {"createiso_allow_reuse": True})
+        compose = helpers.DummyCompose(
+            self.topdir, {"createiso_allow_reuse": True, "sigkeys": ["abcdef"]}
+        )
         old_config = compose.conf.copy()
         old_config["release_version"] = "2"
         compose.load_old_compose_config.return_value = old_config
@@ -1403,12 +1405,30 @@ class CreateisoTryReusePhaseTest(helpers.PungiTestCase):
             phase.try_reuse(cmd, compose.variants["Server"], "x86_64", opts)
         )
 
-    def test_no_old_metadata(self):
+    @mock.patch("pungi.phases.createiso.read_json_file")
+    def test_unsigned_packages_allowed(self, read_json_file):
         compose = helpers.DummyCompose(self.topdir, {"createiso_allow_reuse": True})
         compose.load_old_compose_config.return_value = compose.conf.copy()
         phase = createiso.CreateisoPhase(compose, mock.Mock())
         phase.logger = self.logger
         cmd = {"disc_num": 1, "disc_count": 1}
+
+        opts = CreateIsoOpts(volid="new-volid")
+
+        read_json_file.return_value = {"opts": {"volid": "old-volid"}}
+
+        self.assertFalse(
+            phase.try_reuse(cmd, compose.variants["Server"], "x86_64", opts)
+        )
+
+    def test_no_old_metadata(self):
+        compose = helpers.DummyCompose(
+            self.topdir, {"createiso_allow_reuse": True, "sigkeys": ["abcdef"]}
+        )
+        compose.load_old_compose_config.return_value = compose.conf.copy()
+        phase = createiso.CreateisoPhase(compose, mock.Mock())
+        phase.logger = self.logger
+        cmd = {"disc_num": 1, "disc_count": 1}
         opts = CreateIsoOpts()
 
         self.assertFalse(
@@ -1417,7 +1437,9 @@ class CreateisoTryReusePhaseTest(helpers.PungiTestCase):
 
     @mock.patch("pungi.phases.createiso.read_json_file")
     def test_volume_id_differs(self, read_json_file):
-        compose = helpers.DummyCompose(self.topdir, {"createiso_allow_reuse": True})
+        compose = helpers.DummyCompose(
+            self.topdir, {"createiso_allow_reuse": True, "sigkeys": ["abcdef"]}
+        )
         compose.load_old_compose_config.return_value = compose.conf.copy()
         phase = createiso.CreateisoPhase(compose, mock.Mock())
         phase.logger = self.logger
@@ -1433,7 +1455,9 @@ class CreateisoTryReusePhaseTest(helpers.PungiTestCase):
 
     @mock.patch("pungi.phases.createiso.read_json_file")
     def test_packages_differ(self, read_json_file):
-        compose = helpers.DummyCompose(self.topdir, {"createiso_allow_reuse": True})
+        compose = helpers.DummyCompose(
+            self.topdir, {"createiso_allow_reuse": True, "sigkeys": ["abcdef"]}
+        )
         compose.load_old_compose_config.return_value = compose.conf.copy()
         phase = createiso.CreateisoPhase(compose, mock.Mock())
         phase.logger = self.logger
@@ -1455,7 +1479,9 @@ class CreateisoTryReusePhaseTest(helpers.PungiTestCase):
 
     @mock.patch("pungi.phases.createiso.read_json_file")
     def test_runs_perform_reuse(self, read_json_file):
-        compose = helpers.DummyCompose(self.topdir, {"createiso_allow_reuse": True})
+        compose = helpers.DummyCompose(
+            self.topdir, {"createiso_allow_reuse": True, "sigkeys": ["abcdef"]}
+        )
         compose.load_old_compose_config.return_value = compose.conf.copy()
         phase = createiso.CreateisoPhase(compose, mock.Mock())
         phase.logger = self.logger
diff --git a/tests/test_extra_isos_phase.py b/tests/test_extra_isos_phase.py
index b90deeb0..82a26593 100644
--- a/tests/test_extra_isos_phase.py
+++ b/tests/test_extra_isos_phase.py
@@ -1090,7 +1090,9 @@ class ExtraisoTryReusePhaseTest(helpers.PungiTestCase):
         )
 
     def test_buildinstall_changed(self):
-        compose = helpers.DummyCompose(self.topdir, {"extraiso_allow_reuse": True})
+        compose = helpers.DummyCompose(
+            self.topdir, {"extraiso_allow_reuse": True, "sigkeys": ["abcdef"]}
+        )
         thread = extra_isos.ExtraIsosThread(compose, mock.Mock())
         thread.logger = self.logger
         thread.bi = mock.Mock()
@@ -1104,7 +1106,9 @@ class ExtraisoTryReusePhaseTest(helpers.PungiTestCase):
         )
 
     def test_no_old_config(self):
-        compose = helpers.DummyCompose(self.topdir, {"extraiso_allow_reuse": True})
+        compose = helpers.DummyCompose(
+            self.topdir, {"extraiso_allow_reuse": True, "sigkeys": ["abcdef"]}
+        )
         thread = extra_isos.ExtraIsosThread(compose, mock.Mock())
         thread.logger = self.logger
         opts = CreateIsoOpts()
@@ -1116,7 +1120,9 @@ class ExtraisoTryReusePhaseTest(helpers.PungiTestCase):
         )
 
     def test_old_config_changed(self):
-        compose = helpers.DummyCompose(self.topdir, {"extraiso_allow_reuse": True})
+        compose = helpers.DummyCompose(
+            self.topdir, {"extraiso_allow_reuse": True, "sigkeys": ["abcdef"]}
+        )
         old_config = compose.conf.copy()
         old_config["release_version"] = "2"
         compose.load_old_compose_config.return_value = old_config
@@ -1131,7 +1137,9 @@ class ExtraisoTryReusePhaseTest(helpers.PungiTestCase):
         )
 
     def test_no_old_metadata(self):
-        compose = helpers.DummyCompose(self.topdir, {"extraiso_allow_reuse": True})
+        compose = helpers.DummyCompose(
+            self.topdir, {"extraiso_allow_reuse": True, "sigkeys": ["abcdef"]}
+        )
         compose.load_old_compose_config.return_value = compose.conf.copy()
         thread = extra_isos.ExtraIsosThread(compose, mock.Mock())
         thread.logger = self.logger
@@ -1145,7 +1153,9 @@ class ExtraisoTryReusePhaseTest(helpers.PungiTestCase):
 
     @mock.patch("pungi.phases.extra_isos.read_json_file")
     def test_volume_id_differs(self, read_json_file):
-        compose = helpers.DummyCompose(self.topdir, {"extraiso_allow_reuse": True})
+        compose = helpers.DummyCompose(
+            self.topdir, {"extraiso_allow_reuse": True, "sigkeys": ["abcdef"]}
+        )
         compose.load_old_compose_config.return_value = compose.conf.copy()
         thread = extra_isos.ExtraIsosThread(compose, mock.Mock())
         thread.logger = self.logger
@@ -1162,7 +1172,9 @@ class ExtraisoTryReusePhaseTest(helpers.PungiTestCase):
 
     @mock.patch("pungi.phases.extra_isos.read_json_file")
     def test_packages_differ(self, read_json_file):
-        compose = helpers.DummyCompose(self.topdir, {"extraiso_allow_reuse": True})
+        compose = helpers.DummyCompose(
+            self.topdir, {"extraiso_allow_reuse": True, "sigkeys": ["abcdef"]}
+        )
         compose.load_old_compose_config.return_value = compose.conf.copy()
         thread = extra_isos.ExtraIsosThread(compose, mock.Mock())
         thread.logger = self.logger
@@ -1184,7 +1196,7 @@ class ExtraisoTryReusePhaseTest(helpers.PungiTestCase):
         )
 
     @mock.patch("pungi.phases.extra_isos.read_json_file")
-    def test_runs_perform_reuse(self, read_json_file):
+    def test_unsigned_packages(self, read_json_file):
         compose = helpers.DummyCompose(self.topdir, {"extraiso_allow_reuse": True})
         compose.load_old_compose_config.return_value = compose.conf.copy()
         thread = extra_isos.ExtraIsosThread(compose, mock.Mock())
@@ -1207,6 +1219,38 @@ class ExtraisoTryReusePhaseTest(helpers.PungiTestCase):
             },
         }
 
+        self.assertFalse(
+            thread.try_reuse(
+                compose, compose.variants["Server"], "x86_64", "abcdef", opts
+            )
+        )
+
+    @mock.patch("pungi.phases.extra_isos.read_json_file")
+    def test_runs_perform_reuse(self, read_json_file):
+        compose = helpers.DummyCompose(
+            self.topdir, {"extraiso_allow_reuse": True, "sigkeys": ["abcdef"]}
+        )
+        compose.load_old_compose_config.return_value = compose.conf.copy()
+        thread = extra_isos.ExtraIsosThread(compose, mock.Mock())
+        thread.logger = self.logger
+        thread.perform_reuse = mock.Mock()
+
+        new_graft_points = os.path.join(self.topdir, "new_graft_points")
+        helpers.touch(new_graft_points)
+        opts = CreateIsoOpts(graft_points=new_graft_points, volid="volid")
+
+        old_graft_points = os.path.join(self.topdir, "old_graft_points")
+        helpers.touch(old_graft_points)
+        dummy_iso_path = "dummy-iso-path/dummy.iso"
+        read_json_file.return_value = {
+            "opts": {
+                "graft_points": old_graft_points,
+                "volid": "volid",
+                "output_dir": os.path.dirname(dummy_iso_path),
+                "iso_name": os.path.basename(dummy_iso_path),
+            },
+        }
+
         self.assertTrue(
             thread.try_reuse(
                 compose, compose.variants["Server"], "x86_64", "abcdef", opts