diff --git a/marginaltool b/marginaltool
index 6eac1c2..c5b5acc 100755
--- a/marginaltool
+++ b/marginaltool
@@ -33,7 +33,9 @@ def init(args):
                 args.certfile = config.get(args.url, 'certfile')
             if not args.keyfile or not args.certfile:
                 raise Exception('key or certificate file not specified')
-            args.cert = ''.join(line.strip() for line in open(args.certfile) if not line.startswith('-----'))
+            args.cert = ''.join(
+                cert.split('-----BEGIN CERTIFICATE-----', 1)[1]
+                    .split('-----END CERTIFICATE-----', 1)[0])
 
         case 'pkcs11':
             if not args.id: