You can follow the steps here to use a previous version of the desktop app to extract the keys: https://gist.github.com/gboudreau/94bb0c11a6209c82418d01a59d958c93

The javascript didn’t seem to send the extracted data anywhere, but I did disconnect from the internet while running the script.

Remote wipes are possible. Log into your Apple/Google account, figure out how to find your device, then perform a remote wipe.

That’s the part where the server doesn’t story any information that an attacker could use to log in. The attacker would need the private key, which is stored inside a secure chip on your device (unless you decide to store it in your password manager). All that’s stored server side, is the public key.

When you’re using a password, the server will store a hashed version of that password. If this is leaked, an attacker can attempt to brute-force this leaked password. If the server didn’t properly store hash the password, a leak simply exposes the password and allows the attacker access. If the user didn’t generate unique passwords for each site/server, that exposes them further to password spraying. In that case an attacker would try these same credentials on multiple sites, potentially giving them access to all these accounts.

In case of passkey, the public key doesn’t need to be secret. The secret part is all on your end (unless you store that secret in the managed vault of your password manager).

I do agree that your risk is quite small if you’re already

• using a decent password manager
• doing that the right way
• have enabled 2FA wherever possible

The biggest difference: nothing sensitive is stored on the server. No passwords, no password hashes, just a public key. No amount of brute forcing, dictionary attacks or rainbow tables can help an attacker log in with a public key.

“But what about phising? If the attacker has the public key, they can pretend to be the actual site and trick the user into logging in.” Only if they also manage to use the same domain name. Like a password manager, passkeys are stored for a specific domain name. If the domain doesn’t match, the passkey won’t be found.

https://www.youtube.com/watch?v=qNy_Q9fth-4 gives a pretty good introduction on them.

If this is some kind of messaging board, you’d probably put your public key in your profile (I assume that since OP is talking about the dark web that the posters there would rather not share their actual identity).

Let’s talk about Alice, Bob and Eve. Alice is an active poster on a dark web forum. She puts her public key on her profile and uses the corresponding private key to sign her messages. If Eve wants to pretend to be Alice, Eve can simply put her own public key on her profile and sign messages with her own private key. But Bob is smart. Rather than just looking at the profile of the poster and copying their key every time, Bob saved it in his key store and assigned it to Alice (possibly even marked it as trusted). When Bob sees a post by Eve, he’ll try to validate it. This validation might succeed (if Bob has access to Eve’s public key), but it will be clear that the message wasn’t signed by Alice’s key.

Of course, this all assumes that Bob has quite some knowledge of how this works and is vigilant enough to perform all these validations correctly.

As for the regular internet, there are some services where you can share your public key: keys.openpgp.org is one of these. Of course, as /u/perviouslyiner@lemm.ee says, there’s still the matter of trust. You need to make sure that the public key you’re using is actually from the right person.

What you are doing is exporting your key. Your public key is indeed something you can (and should) share as it enables others to verify that you are indeed who you claim to be (or more accurately, that you’re in control of the private key that’s linked to that public key). So while you should share your public key, your private key must remain private.

What these people on the dark web are doing is one step further: they sign their messages with their private key. This creates a cryptographic signature that’s different for each message (changing a single character in the message will generate a wildly different signature). Anyone with the public key can simply copy that message including the signature and validate it. If even a single character of the message was changed, the signature will not be valid. Thus ensuring others that the person who posted the message is indeed in control of the private key.

Signing is different from encrypting: while encryption renders your message totally unreadable to anyone without the correct key, signing doesn’t change the message itself. It simply appends a signature allowing others to check that the message wasn’t tampered with.