In Keepmark 1.17.0 I am also working on support for AES encryption. This is symmetric encryption - with the use of password. The process of encryption and decryption is much faster than GPG/PGP encryption (which was introduced in the application earlier).
The speed of encryption and decryption makes it a very convenient mechanism to ensure data privacy. As an implementation standard I used here a file format developed by aescrypt.com - so as usual Keepmark will not be the only way to get to your data.
As part of the work on this feature, I also released a Java library to support this format - github.com/tchudyk/filetype-aes.
