If you’re wondering what someone’s been doing in Firefox then you could check the browser history, but if they’ve deleted it, along with any cookies, cache or logins, you won’t learn very much. What isn’t so obvious is that Firefox has a hidden browsing history which records some of the sites you’ve visited, and isn’t removed when you wipe the official "Browsing & Download History". This is all about HSTS (HTTP Strict Transport Security) and HPKP (HTTP Public Key Pinning), web security mechanisms which enable servers to protect against attacks using cookie hijacking, protocol downgrades and fraudulent certificates, among others.… [Continue Reading]