• ricecake@sh.itjust.works
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    17 hours ago

    Sure, all that’s true. But which of those criticisms doesn’t also apply to a password or preshared key? Other than size of key-material, but it’s a fast enough communication medium that any key less than a megabyte is effectively zero.

    I probably don’t need to point out how basically every communication on the Internet is based on public key crypto that we don’t even think about, but I want to ask how you get your shared key to websites when you visit?
    Do you use any tools like signal, telegram and so on?

    My point isn’t that public key systems are perfect, far from it. It’s that it’s wrong to say security and usability are contrary to one another.
    People who think the public key solution is cumbersome are often comparing “no security” to “ideal security”.

    For public key to be secure from man in the middle you need a trusted out of band channel or attestation scheme.
    For a symmetrical key system you need the same channel.
    Without that channel public key has a message interaction where an attacker can swap in their key but is otherwise secure. The symmetric key system is entirely broken.

    “Easy case” public key systems are usually a fair bit more secure than a similar level of effort in other schemes, and likewise a given level of security confidence is easier to get to with public key than a password.

    Finally, and most importantly: your phone quite likely supports multiple levels of authentication.
    You can get into my phone if you have my fingers. This let’s you see my calendar, emails and (many) other things. It doesn’t let you into all of my files, financial apps, or even device settings.