diff --git a/httpsig/utils.py b/httpsig/utils.py
index b34e3fa..fe3f24f 100644
--- a/httpsig/utils.py
+++ b/httpsig/utils.py
@@ -57,7 +57,7 @@ def generate_message(required_headers, headers, host=None, method=None, path=Non
         if h == '(request-target)':
             if not method or not path:
                 raise Exception('method and path arguments required when using "(request-target)"')
-            signable_list.append('%s: %s %s' % (h, method.lower(), path))
+            signable_list.append('%s: %s %s' % (h, method.lower(), path.lower()))
         
         elif h == 'host':
             # 'host' special case due to requests lib restrictions
@@ -124,10 +124,13 @@ def build_signature_template(key_id, algorithm, headers):
     """
     param_map = {'keyId': key_id,
                  'algorithm': algorithm,
+                 'headers': None,
                  'signature': '%s'}
     if headers:
         headers = [h.lower() for h in headers]
         param_map['headers'] = ' '.join(headers)
+    else:
+        del param_map['headers']
     kv = map('{0[0]}="{0[1]}"'.format, param_map.items())
     kv_string = ','.join(kv)
     sig_string = 'Signature {0}'.format(kv_string)