>Do you write your own crypto libraries too?

Some people do. It's a good challenge.[0]

[0] https://cryptopals.com/

To be fair, the main thing you learn doing the cryptopals challenge is to not write your own crypto.

I had a lesson in writing crypto once, when I made what I thought was a good enough secret mixing procedure to encode some data I wanted to email outside of a company that didn’t allow web access. (Long time ago, circa 2000). It all looked undecipherable and I sent most of the data before I discovered that strings of binary zero were leaking my secret key. Oops, pretty stupid.

>To be fair, the main thing you learn doing the cryptopals challenge is to not write your own crypto.

D'oh! Good point though lol.

But the OP clearly didn't ask about doing it as a challenge or to understand how it works (which is what cryptopals is about), but actual usage.

>But the OP clearly didn't ask about doing it as a challenge or to understand how it works (which is what cryptopals is about), but actual usage.

But the parent of the comment I was replying to clearly had the former in mind, as a subsequent comment showed.[0]

[0] https://news.ycombinator.com/item?id=21240429