> This… makes no sense to me. Almost by definition, an AI vendor will have a datacenter full of compute capacity. It feels like this solution has the problem backwards, effectively only limiting access to those
without resources or trying to conserve them.
A lot of these bots consume a shit load of resources specifically because they don't handle cookies, which causes some software (in my experience, notably phpBB) to consume a lot of resources. (Why phpBB here? Because it always creates a new session when you visit with no cookies. And sessions have to be stored in the database. Surprise!) Forcing the bots to store cookies to be able to reasonably access a service actually fixes this problem altogether.
Secondly, Anubis specifically targets bots that try to blend in with human traffic. Bots that don't try to blend in with humans are basically ignored and out-of-scope. Most malicious bots don't want to be targeted, so they want to blend in... so they kind of have to deal with this. If they want to avoid the Anubis challenge, they have to essentially identify themselves. If not, they have to solve it.
Finally... If bots really want to durably be able to pass Anubis challenges, they pretty much have no choice but to run the arbitrary code. Anything else would be a pretty straight-forward cat and mouse game. And, that means that being able to accelerate the challenge response is a non-starter: if they really want to pass it, and not appear like a bot, the path of least resistance is to simply run a browser. That's a big hurdle and definitely does increase the complexity of scraping the Internet. It increases more the more sites that use this sort of challenge system. While the scrapers have more resources, tools like Anubis scale the resources required a lot more for scraping operations than it does a specific random visitor.
To me, the most important point is that it only fights bot traffic that intentionally tries to blend in. That's why it's OK that the proof-of-work challenge is relatively weak: the point is that it's non-trivial and can't be ignored, not that it's particularly expensive to compute.
If bots want to avoid the challenge, they can always identify themselves. Of course, then they can also readily be blocked, which is exactly what they want to avoid.
In the long term, I think the success of this class of tools will stem from two things:
1. Anti-botting improvements, particularly in the ability to punish badly behaved bots, and possibly share reputation information across sites.
2. Diversity of implementations. More implementations of this concept will make it harder for bots to just hardcode fastpath challenge response implementations and force them to actually run the code in order to pass the challenge.
I haven't kept up with the developments too closely, but as silly as it seems I really do think this is a good idea. Whether it holds up as the metagame evolves is anyone's guess, but there's actually a lot of directions it could be taken to make it more effective without ruining it for everyone.