Via Karl Voit we have this Tweet from Tim Dierks offering some pithy but good advice to engineers about crypto:
I’ve been working on Google’s cryptography policy (for engineers). It fits in a tweet: Don’t invent your own algorithms, don’t design your own protocols, don’t code your own implementations, don’t manage your own keys, and do ask for advice.
— Tim Dierks (@tdierks) March 31, 2019
Crypto is notoriously difficult to do correctly; even the experts don’t always get it right. Dierks advice boils down to “Don’t roll your own,” and that’s a good rule.