diff --git a/doc/configuration.rst b/doc/configuration.rst
index df3ca544..950a98c7 100644
--- a/doc/configuration.rst
+++ b/doc/configuration.rst
@@ -435,7 +435,8 @@ Options
 -------
 
 **sigkeys**
-    ([*str* or None]) -- priority list of sigkeys, *None* means unsigned
+    ([*str* or None]) -- priority list of sigkeys; if the list includes an
+    empty string or  *None*, unsigned packages will be allowed
 
 **pkgset_source** [mandatory]
     (*str*) -- "koji" (any koji instance) or "repos" (arbitrary yum repositories)
diff --git a/pungi/phases/pkgset/pkgsets.py b/pungi/phases/pkgset/pkgsets.py
index e570b891..c9ba6426 100644
--- a/pungi/phases/pkgset/pkgsets.py
+++ b/pungi/phases/pkgset/pkgsets.py
@@ -238,7 +238,7 @@ class KojiPackageSet(PackageSetBase):
         pathinfo = self.koji_wrapper.koji_module.pathinfo
         paths = []
         for sigkey in self.sigkey_ordering:
-            if sigkey is None:
+            if not sigkey:
                 # we're looking for *signed* copies here
                 continue
             sigkey = sigkey.lower()
@@ -247,7 +247,7 @@ class KojiPackageSet(PackageSetBase):
             if os.path.isfile(rpm_path):
                 return rpm_path
 
-        if None in self.sigkey_ordering:
+        if None in self.sigkey_ordering or '' in self.sigkey_ordering:
             # use an unsigned copy (if allowed)
             rpm_path = os.path.join(pathinfo.build(build_info), pathinfo.rpm(rpm_info))
             paths.append(rpm_path)