diff --git a/lib/paymentrequest.py b/lib/paymentrequest.py
index f2dbfe29..88ed2589 100644
--- a/lib/paymentrequest.py
+++ b/lib/paymentrequest.py
@@ -128,6 +128,7 @@ class PaymentRequest:
         try:
             x, ca = verify_cert_chain(cert.certificate)
         except BaseException as e:
+            traceback.print_exc(file=sys.stderr)
             self.error = str(e)
             return False
         # get requestor name
diff --git a/lib/rsakey.py b/lib/rsakey.py
index 892c0543..d5ad96e6 100644
--- a/lib/rsakey.py
+++ b/lib/rsakey.py
@@ -14,10 +14,15 @@ import os
 import math
 import base64
 import binascii
+import hashlib
 
 from pem import *
 
 
+def SHA1(x):
+    return hashlib.sha1(x).digest()
+
+
 # **************************************************************************
 # PRNG Functions
 # **************************************************************************