A password that never sits in a digital vault may sound like a contradiction. But that is the idea behind HIPPO, a browser extension built by researchers at Texas A&M University that creates a site-specific password only when you log in, then discards it. For people juggling dozens of accounts, that approach targets a familiar problem. Traditional password managers can help you keep track of strong, unique passwords, but they also concentrate a lot of sensitive information in one place. If that vault is compromised, the damage can spread across many accounts. HIPPO, short for Hidden Password, Password manager Online, takes a different route. Instead of storing passwords locally, in the cloud, or in a browser vault, it asks you to remember one master password. It then combines that with the website’s domain and cryptographic protections to generate a randomized password at the moment you need it. “From the site’s perspective, nothing changes — the website still sees a normal password,” said Dr. Nitesh Saxena, professor of computer science and engineering and associate director of the Texas …