diff --git a/harness/tests/test_registry_evidence_config.py b/harness/tests/test_registry_evidence_config.py
index 89019985..3f7db24a 100644
--- a/harness/tests/test_registry_evidence_config.py
+++ b/harness/tests/test_registry_evidence_config.py
@@ -128,6 +128,18 @@ def test_signed_http_file_requires_explicit_provenance_urls(tmp_path):
     assert_no_canaries(caught.value)
 
 
+def test_signed_http_file_rejects_explicit_null_provenance(tmp_path):
+    secret_file = tmp_path / "signed-urls.json"
+    secret_file.write_text(json.dumps(["https://evidence.example.test/guide.md"]))
+    path = write_config(tmp_path, {
+        "type": "http", "provenance_urls": None, "signed_urls_file": str(secret_file),
+    })
+
+    with pytest.raises(ConfigError) as caught:
+        load_config(path)
+    assert "provenance" in str(caught.value).lower()
+
+
 def test_public_http_rejects_inline_query_bearing_transport_urls(tmp_path):
     path = write_config(tmp_path, {
         "type": "http",
diff --git a/harness/tht/config.py b/harness/tht/config.py
index 102e6b99..040bdf1f 100644
--- a/harness/tht/config.py
+++ b/harness/tht/config.py
@@ -60,7 +60,12 @@ def _resolve_http_signed_url_files(value: Any) -> Any:
             return resolved
         if "urls" in resolved:
             raise ConfigError("HTTP signed URL file cannot be combined with urls")
-        if "provenance_urls" not in resolved:
+        provenance_urls = resolved.get("provenance_urls")
+        if (
+            not isinstance(provenance_urls, list)
+            or not provenance_urls
+            or any(not isinstance(item, str) or not item for item in provenance_urls)
+        ):
             raise ConfigError("HTTP signed URL file requires provenance_urls")
         path_value = resolved.pop("signed_urls_file")
         if not isinstance(path_value, str):