Anime Catgirls and the Linux Kernel: A Cost Analysis of an Anti-Crawler Mechanism

Recently, more websites are using Anubis, an anti-crawler system that uses a mining-like process to verify visitor identity, requiring users to perform SHA-256 operations to gain access. The author questions the effectiveness of Anubis because it's trivial for AI crawlers with powerful computing capabilities but inconvenient for ordinary users. Through calculations, the author finds that even with tens of thousands of websites deploying Anubis, the cost of cracking its verification mechanism is virtually zero. The author finally provides a simple C program to bypass Anubis's restrictions and points out a vulnerability in the Anubis system.