# EFSEXT > [HTML Version](efsext_sp.htm) **EFSEXT=ext1 \{,ext2, ext3,...ext10\}** EFXEXT specifies which file extensions are to be encrypted. An encrypted file will be created if the following conditions are met: • The file is being created with either OPEN for output or ALLOCATE • The extension is in the EFSEXT list • A-Shell's Encrypted File System (EFS) is licensed and enabled • EFS has not been disabled via XCALL ASFLAG,1024 Note that [EFS](efssbr.htm.md) is an entire system for file encryption and security. It is not included in the standard release of A-Shell, must be licensed as an option, and should be carefully considered before being implemented. If you are interested in implementing this filing system, see the documentation on the subroutine [EFS](efssbr.htm.md) and contact MicroSabio to discuss.