working on gtk3 gui
CHANGELOG:
* added encryption;
* added hmac;
* small code improvement;
CHANGELOG:
* fixed encryption process;
* improved security;
* small fixes;
CHANGELOG:
* added decryption process;
* code improvement;
* added file deletion process;
CHANGELOG:
* added hash computation;
* more small improvement;
CHANGELOG:
* updated readme;
* updated makefile;
minor changes