That is an opinion editorial by Shinobi, a self-taught educator within the Bitcoin house and tech-oriented Bitcoin podcast host.
I counsel, earlier than studying this, that you just learn the prior article I wrote explaining what Nostr is and the way it works at a excessive stage. It’s best to then have a good suggestion of the core design of the system at that time, so now let’s check out probably issues which are going to happen because it grows in adoption. With the platform changing into a well-liked one for the Bitcoin group, these issues are ones to concentrate on.
As I mentioned within the prior article, person public/personal key pairs are integral to how Nostr works as a protocol. There aren’t any usernames, or any kind of identifiers {that a} relay server is in charge of, to affiliate to particular person customers. It’s merely these customers’ keys which are fully below their management.
This capabilities as a decent binding between the precise person and the way they’re recognized by others that stops any relay server from unbinding these two issues, i.e., giving somebody’s identifier to a different person. This solves one of many largest elementary issues of platforms used for communication between individuals: the shortage of management over customers’ personal identities. However it additionally introduces the entire issues of key administration that somebody possessing a non-public key runs into. Keys will be misplaced and keys will be compromised and if such an occasion have been to happen, customers have nobody to go to for help, similar to with Bitcoin. There isn’t any buyer assist to recuperate something. You lose it, that is it.
That is going to inevitably necessitate a scheme for customers to rotate from one keypair to a different in a method that’s verifiable and discoverable for different customers that they work together with by way of the protocol. All the protocol is predicated round proving that an occasion got here from a particular person (identification key), so all of these ensures exit the window as soon as somebody’s keys are compromised.
How do you deal with that? Simply go examine their Twitter account? Properly, then that is not a really decentralized system, finally, if you happen to require utilizing a centralized platform the place they aren’t in charge of their identification to confirm their Nostr identification.
Produce other customers attest to the legitimacy of a brand new key? That does not tackle conditions reminiscent of mass key compromises, or not realizing anybody near them effectively sufficient to belief their attestation.
Nostr wants an precise cryptographic scheme tying the rotation of 1 key to a different. There’s a proposal from developer fiatjaf for a fundamental scheme that might doubtlessly resolve this subject. The essential concept can be to take a protracted set of addresses derived from a single grasp seed, and create a set of “tweaked” keys much like how Taproot bushes are dedicated to a Bitcoin key. Taproot takes the Merkle tree root of the Taproot tree and “provides” it to the general public key to create a brand new public key. This may be replicated by including that Merkle tree root to the personal key with the intention to attain the matching personal key for the brand new public key. Fiatjaf’s concept is to chain commitments going backwards from the top to the start so that every tweaked key would truly include a proof that the following tweaked key was used to create it.
So, think about beginning with key Z, the final one within the chain. You’d tweak this with one thing, after which go backwards and create a tweaked model of key Y utilizing the tweaked Z key (Z’ + Y = Y’). From right here you’ll take Y’ after which use it to tweak X (Y’ + X = X’). You’d do that all the way in which again to key A, to get A’, and from there, start utilizing that key. When it’s compromised, the person can broadcast an occasion containing the untweaked key A and tweaked key B’. This is able to include the entire knowledge wanted to point out B’ was used to generate A’, and customers may instantly cease following A’ and comply with B’ as a substitute. They’d know definitively that B’ is that person’s subsequent key and to comply with that as a substitute.
This proposal nonetheless has some issues although. First, you must generate the entire keys you’ll ever use forward of time and it has no solution to rotate to an entire new set of keys. This might be handled by committing to a grasp key on this scheme that might notarize such rotations, or just producing a really giant set of keys from the start. Both path can be a sound course to take, however finally would require conserving a root key or key materials secure and solely exposing particular person hotkeys to Nostr purchasers.
This scheme, nonetheless, does nothing to guard customers or supply a mechanism for identification restoration within the occasion that the foundation key materials is misplaced or is itself compromised. Now, this is not to say that there isn’t a profit to fiatjaf’s scheme, there completely is, but it surely’s essential to make the purpose that no resolution solves each downside.
To preach a bit on potential options right here, think about as a substitute of a sequence of tweaked keys like he proposes, {that a} secret is tweaked with a grasp chilly key that should even be used to signal the occasion rotating from one key to a different. You might have key A’, which is derived by including A and M (the grasp key), and the rotation occasion can be A, M and B’ (generated by including B and M) with a signature from M. M might be a multisig threshold key — two of three, three of 5, and so forth. This might doubtlessly add redundancy towards loss in addition to present a safe mechanism for key rotation. This opens the door as effectively to utilizing companies to assist in restoration, or spreading a few of these keys round to trusted buddies. It gives the entire identical flexibility as multisig does with Bitcoin itself.
NIP26 can also be a proposal that might be very helpful in dealing with this downside. This specifies a protocol extension to occasions permitting a signature from one key to authorize one other key to publish occasions on its behalf. The “token,” or signature proof of delegation, would then be included in all occasions posted by the second public key on the primary’s behalf. It could even be time restricted in order that delegation tokens mechanically expire and must be renewed.
Finally, nonetheless it’s solved, this downside has to be solved for Nostr in the long run. A protocol primarily based totally on public/personal key pairs getting used as identities can’t acquire traction and adoption if the integrity of these identities can’t be protected and maintained for customers. That ultimately will boil right down to having to continually use out-of-band and centralized platforms to confirm new keys and coordinate individuals following your new identification when one thing is misplaced or compromised, and at that time, these different platforms grow to be a way to sow confusion and interact in censorship.
Problems with key administration and safety are massive issues with a really giant design house filled with commerce offs and ache factors, however they’re issues which are going to must be solved inside the context of Nostr for it to work. In my subsequent article, I’ll summarize some points that I see cropping up with regard to relay server structure and scaling points that Nostr builders must confront given the essential knowledge constructions that Nostr is constructed on.
For anybody studying and questioning why I have not talked about decentralized identifiers (DIDs): Sure, that may be a potential resolution to those issues that, for my part, is sort of complete. Nevertheless, Nostr builders appear very hesitant to combine DIDs into the protocol or purchasers attributable to the truth that it might create exterior dependencies exterior of the Nostr protocol. In case you are not accustomed to how DIDs work on a technical stage and have an interest, this text by Stage 39 is a really effectively written summarization of how they work.
This can be a visitor publish by Shinobi. Opinions expressed are totally their very own and don’t essentially mirror these of BTC Inc or Bitcoin Journal.