to secure a directory

[Karim]

Hello ! Here is my problem : I wrote 2 codes : a server under linux and client for linux (and windows). The server sends datas to a client (which is on an other computer denoted  by C) and the connection is secured using openssl. The client stores those datas in a directory of C but I would like that nobody could access to this directory but the administrator of C (the root) can :( . So I thought that I could crypt the files which are in this directory using functions of openssl. But the datas which are in the directory have to be used by a code which is in this directory and I want the datas still remain crypted. So is it possible to do all that ? Thanks a lot for your help ! Karim