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 un...