SQl server 2008 permission and encryption

Question

i have made columns in some of the tables encrypted in sql server 2008. Now as i am a db owner i have the access to encode and decode the data using the symmetric key and certificate. But some other users have only currently datareader and datawriter rights ,and when they execute any SP referring the logic which uses the key and certificate "User does has not right on the certificate to execute". What rights / exact permission should i grant them just to solve this problem

Answer 1

Thanks to Dynamo ,the solution is GRANT CONTROL ON CERTIFICATE :: certificate_name TO username

http://serverfault.com/questions/122851/sql-server-2008-permission-and-encryption