Tools that allow government hackers to break into iPhones and Android phones, popular software like the Chrome and Safari browsers, and chat apps like WhatsApp and iMessage, are now worth millions of dollars — and their price has multiplied in the last few years as these products get harder to hack.

On Monday, startup Crowdfense published its updated price list for these hacking tools, which are commonly known as “zero-days,” because they rely on unpatched vulnerabilities in software that are unknown to the makers of that software. Companies like Crowdfense and one of its competitors Zerodium claim to acquire these zero-days with the goal of re-selling them to other organizations, usually government agencies or government contractors, which claim they need the hacking tools to track or spy on criminals.