I also wrote https://github.com/paragonie/halite which is a PHP library aims to make libsodium incredibly easy for PHP developers to get right.
For systems that need asymmetric crypto and can't install libsodium, I also wrote https://github.com/paragonie/EasyRSA which side-steps a lot of the mistakes developers make. EasyRSA uses defuse for symmetric-key encryption, then encrypts the AES key with RSA.
Writing secure cryptography isn't trivial. Assuming the three projects I just linked to are secure enough to use (all indications point to: they are), there's literally no reason to reinvent the wheel solely for Magento.
Magento already uses Composer; they could just add them to their composer.json file and rewrite their routines to use defuse + maybe EasyRSA if they have a use case for it.
Zend\Crypt is also an acceptable choice, as long as you don't install the version with an RSA implementation vulnerable to padding oracle attacks. https://framework.zend.com/security/advisory/ZF2015-10
It's easy to look at one small part of a codebase and say "this is wrong", but to get it right you have to learn large chunks of the code. Be aware what level of work you are shoving onto the author in your comment.
I didn't like my magento job much :/
Magento is very much open-core in all practical terms.
https://magento.com/company/press-room/press-releases/magent...