Modify C written Opensips to read 7z archive.

I need to modify open source program called opensips ([login to view URL]). It reads unencrypted plain text configuration from /etc/opensips/[login to view URL] text file, I would like to encrypt this config file with 7z aes-256 algorithm and given constant password. Opensips should be able to read encrypted configuration file instead of plain text file. Password is constant and should be stored in opensips in such way, that after decompiling compiled opensips it will be hard to find.