This is something I don't fully understand, so it's hard for me to summarize it or find the shortest relevant quote to share with you. Sorry.
[TL;DR]Keybase sounds a little bit like a filesystem similar to
IPFS, but with encryption built-in and made super easy. You don't have to know someone's Keybase account info to connect with them. You can create encrypted, shared files/folders with someone who doesn't even have a Keybase account. If you only know them on Twitter, you can use their Twitter account name, and Keybase will allow them (and you?) to link the Twitter handle to their Keybase account (when they finally create one).
For more info, check out this page on Keybase, which is more colorful and has lots of pictures and visually pleasing things and is written by someone who knows what they're talking about:
https://keybase.io/i...e-keybase-filesystem[/TL;DR]It has public directories shared with everyone as well as private ones, shared with no one or only the people you select.
Quote related to Public directories:
Public, signed directories for everyone in the world
You can now write data in a very special place:
/keybase/public/yourname
Every file you write in there is signed. There's no manual signing process, no taring or gzipping, no detached sigs. Instead, everything in this folder appears as plaintext files on everyone's computers. You can even open /keybase/public/yourname in your Finder or Explorer and drag things in.
Quote related to Private directories:
But there's more!
Keybase mounts end-to-end encrypted folders in /keybase/private.
/keybase/private/{people}
This is your own encrypted folder, just for you:
/keybase/private/yourname
And here's a folder only you and I can read. You don't have to create this folder, it implicitly exists.
/keybase/private/yourname,chris
Again, maybe you know me on twitter, and prefer to assert that:
/keybase/private/yourname,malgorithms@twitter
These folders are encrypted using only your device-specific keys and mine.
The Keybase servers do not have private keys that can read this data. Nor can they inject any public keys into this process, to trick you into encrypting for extra parties. Your and my key additions and removals are signed by us into a public merkle tree, which in turn is hashed into the Bitcoin block chain to prevent a forking attack.
And more about sharing with people who don't even use Keybase (yet):
Frictionless sharing
Soon, you'll be able to throw data into /keybase/private/yourname,pal@twitter, even if that Twitter user hasn't joined Keybase yet. Your app will encrypt just for you and then awake and rekey in the background when that Twitter user joins and announces a key.
And it may even answer
the question about signing code which was asked by f0dder a few days ago:
Encryption's a pleasure...but what about verifying some source code release or announcement online? Keybase to the rescue; files, messages, streams: all can be signed, encrypted, decrypted, verified, with a keybase username.
Verifying a signature from someone you don't know will summarize all their public accounts and check them for you to make sure the signatures match up.
