SSIS Package - user modifications

Hi SSIS Experts,

I have a scenario where, the packages created by me will be run by other user (unknown), but i need to ensure that the package will not be opened by unknown user for modification.

Now to stop this i have tried :

1> Encrypt all with password but the password is visible when the job is been script job as --> create to in the SQL Job agent

Now in this scenario the unkown person might even open the package and modify ...which is not expected.

Or

Can we try to deploy the same package via some script and restrict the user from modifying it.

Any ideas .....