For many years, encryption tools have been widely available in operating systems. One of them is OpenSSL, open sourced and widely available in different platforms; it provides many strong encryption options. The commercial application RAR is versatile and also built for several platforms. Altogether they can generate segmented archives highly protected that will enable us reliable storage in external facilities, with the added capability of managing the archives with widespread, almost-standard, tools. In order to synchronize files with the storage device, SecureFolders is front-end also to RSync, another widespread usage utility that keeps twin folders up to date.
SecureFolders is a "front-end", a user interface that controls the command line applications rar, openssl and rsync. Therefore, any user could open (knowing the password) the encrypted files without dependency on a single application. This fact is to the advantage of the user, because won't get trapped by a tool that ceases maintenance, or uses a unusual format, or, simply, must use the files in another machine without this front-end.
Some of its features: