By the way, neither identity protection nor reuse across browsers does not strictly require IdP. In a strict sense, you don&#x27;t need a trusted third party to transfer data between your devices or have a means to recover a lost key. If you have everything you need to prove your identity claims, you can decide how you handle those on your own, and whenever you want some TTP assistance or not.<p>And if you decide you do, the requirements are a lot more relaxed. With Persona you trust a very specific third party - some email provider. You trust it to behave and you trust it to serve and stay so for as long as you need your identity.<p>However, if - for example - you have an identity asserted by a keypair - you have way more possibilities, ranging from a key backup in a tamper-resistant HSM in a safe vault behind a blast-resistant doors in your basement, or setting up a secret sharing scheme where 3 out of 6 your close friends must get together to help you recover a lost key, to just uploading your key to Dropbox and not giving a damn. Isn&#x27;t that a good thing?<p>And if the key&#x27;s completely lost - it&#x27;s the same as if the email provider&#x27;s gone - you&#x27;ll have to either give up or recover your accounts using some other ways (talking to a support and figuring out what would be a good replacement proof).