diff --git a/lib/blockchain.py b/lib/blockchain.py
index 10bf9a84..2159abf3 100644
--- a/lib/blockchain.py
+++ b/lib/blockchain.py
@@ -353,8 +353,10 @@ def scriptpubkey_to_canonical_address(scriptpubkey):
         signatures_required = asm[0]
         signatures_possible = len(asm) - 3
         return "_".join([str(signatures_required)] + sorted(scriptpubkey['addresses']) + [str(signatures_possible)])
-    else:
+    elif 'addresses' in scriptpubkey:
         return scriptpubkey['addresses'][0]
+    else:
+        return None
 
 
 def get_unspent_txouts(source, return_confirmed=False):