error 15466 An error during decryption I have a stored procedure that runs xp_cmdshell with a user with sysadmin right.(it was created by someone else long time ago). For security purposes I need to remove the sysadmin right from this user. 
So I created a proxy account and gave execute privilege to this user on the xp_cmdshell (practically followed the steps how to run xp_cmdshell with a non sysadmin user ).
But when I run the stored procedure I am getting the below error:


  error number 15466    severity 16  errorline 1    An error occurred during decryption.


I use SQL Server 2008

What could be the problem?
This is most likely occurring as the old user ( the one with sysdmin rights) had access to the SQL Server Symmetric Keys which are used to encrypt/decrypt keys which the new user does not.

The Grant Symmetric key article provides details and the links at the end provide some good reading.