There are a lot of comments touting using public keys for this.
So, you have one laptop and one mobile phone. How do you set up your "password" on both? Assume you're not "technical".
Next: your car (or apartment, etc.) is robbed. You lose both devices. OR: water damage. Whatever. You're away from home with one device, and its battery dies, wifi fails, whatever.
No worries, your brother/friend/colleague lends you a device. But... you're locked out of EVERYTHING on that device. All of your accounts require your public key, and you obviously don't have that at an internet cafe, or even at your brother's house, on a computer you're comfortable is safe.
Use the same keyring on both devices. It’s just a file, copying it over shouldn’t be a problem.
Then ascii-armor that file and print it out and/or store it on a CD, keep that in a (or possibly multiple) safe location(s). You could even give your brother the key and trust him not to try to crack the passphrase.
This is a solved problem. Look at CAC/PIV smartcards. Virtually anyone with a computer is used to carrying around a credit card or ID card. Just add a PK circuit.
All of the problems I mentioned are solved for technical users, or special situations with the right equipment available (like a CAC reader... I certainly don't have one of those integrated into my mobile phone, or laptop for that matter).
That doesn't help when we need a general solution with usability that comes close to remembering a password.
a few one time keys? the way google backup codes work. I am heavy RDP user. One of the things I hate about windows is the inability to have one time burn passwords.
So, you have one laptop and one mobile phone. How do you set up your "password" on both? Assume you're not "technical".
Next: your car (or apartment, etc.) is robbed. You lose both devices. OR: water damage. Whatever. You're away from home with one device, and its battery dies, wifi fails, whatever.
No worries, your brother/friend/colleague lends you a device. But... you're locked out of EVERYTHING on that device. All of your accounts require your public key, and you obviously don't have that at an internet cafe, or even at your brother's house, on a computer you're comfortable is safe.