diff --git a/sbom/examples/rpm/from-koji.py b/sbom/examples/rpm/from-koji.py
index 14a826f..de1c849 100644
--- a/sbom/examples/rpm/from-koji.py
+++ b/sbom/examples/rpm/from-koji.py
@@ -311,7 +311,7 @@ def handle_srpm(filename, name):
             {
                 "referenceCategory": "PACKAGE-MANAGER",
                 "referenceType": "purl",
-                "referenceLocator": f"pkg:rpm/redhat/{name}@{version}-{release}?arch={arch}&checksum={digest}",
+                "referenceLocator": f"pkg:rpm/redhat/{name}@{version}-{release}?arch={arch}&checksum=sha256:{digest}",
             }
         ],
         "checksums": [