Samba files Encryption

Assuming the windows clients are using an Office package, my suggestion would be to use the document encryption function within the package. Then only members of the group need to know the password.

Hope this helps.

Do you really need encryption ?
If the security of the Samba is propper configured and the access restrictions on the shares are placed it will not be possible to access the shares.

For configuring the Samba look at https://www.techrepublic.com/forumqa/thread_detail.jhtml?thread_id=98329 .

If you use Share level security the user can only access the share with the knowledge of the password.
If you use the User level the authentication will take place on the Linux machine on which you canadd groups and give the share group or username access.
If you use the Server level make sure the groups and or users are propperly configured on the authentication server

Using Samba as authentication server offers enough security.
For a detailled ('book') description go to http://samba.he.net/using_samba/
especially chaper 6 http://samba.he.net/using_samba/ch06_01.html
should show you that an extra encryption isdefinitely not necessary
the_shelter