|27.10.16.Controlling access to packages|
You can do this in one of two ways: a simple command or a wrapper package.
To grant a user rights to access a particular package:
grant execute on package_name to user
You can't grant rights to execute a portion of a package.
Rights must be granted to an entire package.
To revoke grants from a user, use the following command:
revoke execute on package_name from user