diff --git a/pegleg/engine/catalog/pki_utility.py b/pegleg/engine/catalog/pki_utility.py
index e39212ed..a755d237 100644
--- a/pegleg/engine/catalog/pki_utility.py
+++ b/pegleg/engine/catalog/pki_utility.py
@@ -350,7 +350,8 @@ class block_literal(str):
 
 
 def block_literal_representer(dumper, data):
-    return dumper.represent_scalar('tag:yaml.org,2002:str', data, style='|')
+    return dumper.represent_scalar(
+        'tag:yaml.org,2002:str', str(data), style='|')
 
 
 yaml.add_representer(block_literal, block_literal_representer)