Cryptix is described as 'complete solution to study cryptography, encoding and ciphers. Hide your datas, encrypt your texts and documents'. There are five alternatives to Cryptix for a variety of platforms, including Linux, Mac, GnuPG, OpenPGP and Xfce. The best alternative is GnuPG, which is both free and Open Source. Other great apps like Cryptix are Kleopatra (Free, Open Source), GPG Suite (Paid, Open Source), Autocrypt (Free, Open Source) and oPenGP (Paid).
GnuPG allows to encrypt and sign your data and communication, features a versatile key management system as well as access modules for all kinds of public key directories. GnuPG, also known as GPG, is a command line tool with features for easy integration with other applications.