Fair point. But what I'm getting at is that if you aren't an expert on cryptography (and perhaps even if you are!) rather than imposing your personal preferences on others simply deferring to a trusted third party library can make a lot of sense.

So in addition to a sensible default I guess it would also be a good idea to tag choices that you believe to be outdated with a large warning. That way you haven't rolled your own crypto, you haven't forced your views on others, but you have done your best to enable end users to operate your tool in a sensible manner.