diff --git a/src/cutecoin/core/account.py b/src/cutecoin/core/account.py
index c1e4e235553e71d3933bd5890318e52e2c68abfc..52b47a12695c96e098112a596a9cffb7810ef2cd 100644
--- a/src/cutecoin/core/account.py
+++ b/src/cutecoin/core/account.py
@@ -189,7 +189,7 @@ class Account(object):
                           block_hash, type, selfcert.uid,
                           selfcert.timestamp, None)
         key = SigningKey(self.salt, password)
-        membership.sign(key)
+        membership.sign([key])
         logging.debug("Membership : {0}".format(membership.signed_raw()))
         community.post(bma.blockchain.Membership, {},
                        {'membership': membership.signed_raw()})