Securing a file with UBX is like putting a sensitive document in an infinitely thick vault that can only be opened with the correct password. UBX 1600-bit symmetric data encryption was already an unbreakable vault. Now UBX is 8800-bit for your peace of mind.
All characters and all symbols from all languages are supported in passwords and hints. If you can type it, you can make it your password. Get creative, but don't get carried away. There's no password recovery or "backdoor" or master key, so don't forget the password.
The core, the heart, the main attraction of UBX is the jumble. The stream cipher randomizes the file contents, and then the jumble cipher randomizes the order of the contents. Thanks to its huge block size (up to 128MB) and slow speed, the jumble cipher is the ideal method of encryption for archived data.
A key file is like a really long password. The maximum lengths are 510 bytes for passwords and 65536 bytes (64KB) for key files. Any file can be a key file.