The use of the word "expert" here gives me pause.
I thought one of the motivations behind this library was that you did not need to be an "expert" to use it.
I thought one of the motivations behind this library was that you did not need to be an "expert" to use it.
Even using NaCl, one needs to understand enough of what's happening under the hood to properly reason about the security of the whole system they've built.
https://github.com/TLINDEN/pcp/blob/master/libpcp/crypto.c#L...
That's, like, 5 minutes worth of looking, most of it spent working out how to get from main() to the part of the code that actually starts taking attacker-controlled inputs; we're about 10 lines into the code that handles those inputs. Is that a real vulnerability? Hell if I know, but I'm scared of this code.
Which is not to say I don't like it. There's a small utility function in there I'm stealing! The author is clearly smart and I hope this was an interesting project for them. But I don't recommend using this for real --- and I think neither does the author.
Some years ago, there was another fellow who wrote a set of NaCl utilities that were very simple, UNIX filters. While I was "scared of the code" because he's not a renown cryptographer (does he need to be?), I was thankful for a simple, working example. There really weren't any publicly available at the time.
I really appreciate when people share these self-learning projects.
And yes I do not recommend using this for serious purposes (that is, I am the author).
On my end, I always tell them any system or scheme is to be assumed vulnerable until proven otherwise through analysis and pentesting. If they doubt that, I show them plenty of stuff made by pro's and associated CVE's. Then ask if their people were better and with more budget for security. Usually a no...
Using these features should still be done under the guidance of someone who knows what they're doing. There's a larger number of developers who can use libsodium than there are developers who could replace it on their own.
In a sense, NaCl/libsodium can be viewed as a "replacement for expertise" that is so rare it's nigh-nonexistent. (To wit: these libraries were created by multiple authors.) Rather, it places the capability to build solid application-layer crypto into the hands of mere mortals.
That doesn't obviate the need for good mortals. :)