I didn't agree with this idea, but then I looked at how much HN karma you have and now I think that maybe this is a good idea.
And to bring this back to the original arxiv topic. I think reputation system is going to face problems with some people outside CS lack of enough technical abilities. It also introduce biases in that you would endorse people who you like for other reasons. Actually some of the problems are solved and you would need careful proposal. But the change for publishing scheme needs push from institutions and funding agencies. Authors don't oppose changes but you have a lobby of the parasitic publishing cartel that will oppose these changes.
I don't think publishing a PGP key with your work does anything. There's no problem identifying the author of the work. The problem is identifying _untrustworthy_ authors. Especially in the face of many other participants in the system claiming the work is trusted.
As I understand it, the current system (in some fields) is essentially to set up a bunch of sockpuppet accounts to cite the main account and publish (useless) derivative works using the ideas from the main account. Someone attempting to use existing reasearch for it's intended purpose has no idea that the whole method is garbage / flawed / not reproducible.
If you can only trust what you, yourself verify, then the publications aren't nearly as useful and it is hard to "stand on the shoulders of giants" to make progress.
Is it though? Should we care about authors or about the work? Yes, many experiments are hard to reproduce, but isn't that something we should work towards, rather than just "trust" someone. People change. People do mistakes. I think more open data, open access, open tools, will solve a lot, but my guess is that generally people do not like that because it can show their weaknesses - even if they are well intentioned.