Are we self-sovereign PKI yet?
buffrr.dev
buffrr.dev
As for the solution, it seems to explicitly not address recovery of lost keys/identities, which is however exactly the part that makes this hard for regular users.
That, and general name confusion attacks, I suppose: "I'm lxgr17@key, yeah, don't ask about the first 16. Oh also make sure 'key' is not the one with the Georgian lowercase e in the middle, that one's an impostor. Wait, actually, let me quickly spell it out in hexadecimal Unicode points..."
At least blockchain addresses have that going for them: They're way too long to even try and remember or spell out on the phone.
People have been coming up with these schemes for decades, and for that entire time, the near-universal de facto standard trusted identity system has been "Google accounts". People knew at the beginning that they were delegating trust to Google; they know it now as well; they are not going to adopt "names resolve to a key, the same key, in every application", no matter how many different names that scheme is given.
Key loss is hard but not insurmountable. Social recovery / split-key custody seem like the right direction. Apple uses "recovery contacts" if you have advanced data protection enabled. A friend holds one share, Apple holds another but neither can recover alone. that's social recovery + split-key shipping to hundreds of millions of devices today
> That, and general name confusion attacks, I suppose: "I'm lxgr17@key...
pre-registering the obvious typo neighbors (lxrg, 1xgr ... etc) and it's cheap since handles batch-issue off-chain under a fixed 32-byte root, and strict ascii only charset ... etc could help mitigate some of this.
I think the exact and trusted data-movement is the hard part. If we could instantly transcribe a 150 digit number (~512 bits) from eye to fingertips, then the actual memory/comparison could be done in any pocket-calculator, with X-Y==0.
The scheme described in the system seems to use a blockchain to create a shared mapping between a name and a cryptographic identity. So a third party is still in control of that mapping, but there are a lot of third parties and most of them would have to conspire to forge a mapping. Then you could send a message to a name, rather than a number, with confidence that someone in the past picked that name and locked in the mapping between that name and the cryptographic identity.
The append-only, distributed nature of the traditional SKS PGP keyserver network seems to provide the same sort of thing. If you query several keyservers you can be reasonably sure that someone mapped a name (and email address) to a particular cryptographic identity sometime in the past. A single server operator can not forge a mapping without the possibility of that forgery being detected.
The thing is, people don't actually want a reliable name to cryptographic identity mapping service for end to end encrypted messaging. They instead want to be sure that they are securely exchanging messages with an particular flesh and blood person, and if you want to insure that you are back in the realm of ridiculously long numbers.
> most of them would have to conspire to forge a mapping.
The mapping is recorded in an immutable ledger (bitcoin) so forging is not feasible without breaking Bitcoin's proof of work. its a stronger guarantee than a key server.
> They instead want to be sure that they are securely exchanging messages with an particular flesh and blood person
comparing fingerprints doesn't verify a flesh-and-blood human either. "is this the specific person I mean" problem is still real and separate though.
`grace@key` binding gives you a stable, human-readable identifier you can hand out like an email address, build reputation on, and that anyone can use to verify posts made by you and message you without having to meet you in person. It solves the UX of using public keys as your identity. You can post online with a public key as your id (e.g. nostr) but its harder to build your online identity around it.
you can rotate the key underneath the name. with a bare key it becomes your identity, so rotating means becoming a new person and re-verifying with everyone.
> you are back in the realm of ridiculously long numbers.
not really. the long number is a disposable part, and there's a name above it. You can still exchange "grace@key" in person, and be sure you're talking to "grace@key"
You want to be sure it's a particular person the you need to establish in-person trust.
This is impractical and the opposite of what we want. It's a required ID to use the internet, monitored by governments, tracked by corporations, and forever unchanging.
What we need is a system that allows people to easily create new IDs, that updates contacts that people choose. Think of a contact book that sends new keys to all contacts on every change. (Contacts would need to be always online.) It could update the key used on a website or not, depending on the users choice.
Breaking tracking and required IDs means flux and churn.
There are clearly two opposing requirements.
One for anonymity, where people who need to be anonymous can create an identity that is verifiably the same person each time, but not a specific, identifiable, individual. The classic example is journalistic sources.
One for trust and verification, where the identity needs to be absolutely, permanently, associated with a specific individual. Online banking is the classic example here.
I don't think the same system can be used for both.
- If we can create multiple identities without verifying the human each time, as you say "flux and churn", then the second requirement is broken - there is no link between the identity and a verifiable person so the identity can't be trusted.
- If we can't create multiple identities without verifying the human each time, then the first requirement is broken - every identity can be associated with a specific human and there's no anonymity.
We could try some hybrid system where some identities are known people, and others are pseudonymns. But that feels like two systems wedged into the same box. The hard problems of absolutely correctly identifying a human so the second system works is still not solved, and irrelevant to the first system.
You are absolutely correct that the system that identifies individuals is incredibly attractive for states and large corporations, and so incredibly dangerous for actual humans. We need to be very, very, careful with this.
> Contacts would need to be always online.
That also sounds impractical.
> It's a required ID to use the internet
How does any of that follow? Having a reusable self-sovereign ID format for those scenarios where people want to share it is very different from having an authority-issued ID format that's mandatory for some interaction.
As a concrete example: I have an iMessage (CKV), Signal, WhatsApp, and GPG identity key, but I don't need to provide any of them when ordering pizza online. But what I can't do is choosing to use the same key for my same number on both e.g. Signal and iMessage to make it easier for people to switch between messengers without having to re-verify me.
A hypothetical shared key format would fix that, but would (hopefully!) still allow me to create multiple keys/identities for multiple contexts, and to not provide any persistent identity when it's not necessary.
Always online is no different than an email account or website, and the rate of change would be, at least, minutes not seconds.
The lack of an interoperable key standard isn’t stopping them. (In fact, it’s even helping a bit by providing cover for MITM snooping)
I can foresee there will be valid use cases to re-assign a number (e.g. stolen, mistyped, wrongly assigned etc). One thing I learned about a real-world database for human information -- there will be a valid use case to do _anything_.
Who can update and publish the merkle trie onto the blockchain? Is it only Spaces themselves who can? If so, this seems a little inferior to more direct blockchain solutions like the Ethereum Name Service which exists as a smart contract on a blockchain that anyone can use directly.
they don't have much power besides adding your name -> pubkey binding in the tree.
Having studied this problem space for some time, this is also my read of what the ultimate solution requires. That said, as the author also mentions, the biggest challenges in this paradigm are social, not necessarily technical. Therefore, I think the new solution requires a protocol approach rather than just a technical standard or implementation.
The KERI protocol (https://keri.one/) has been the best attempt I've seen at this. They focus on a similar concept, persistent long lasting identifiers built on top of cryptographic primitives, but they do so with a microledger approach than a monolithic blockchain as the root. The core primitive is what is known as a Key Event Log which tracks verified attestations of key transactions such as issuance, revocation, delegation, rotation, interaction, and so on. It is a very powerful concept that then facilitates stronger trust assumptions via end-to-end verification. And maybe most importantly, enables some very clean key management procedures that then can anchor the protocol behavior needed to optimize for those social challenges discussed earlier.
Regardless, adoption of KERI and other solutions like Spaces has not been very productive. I fear we've reached a tipping point where the external threats are too large now and top-down authoritarian-like solutions that address these issues head on will be the winners, leaving out dociety with very poor tradeoffs in such a critical area.
> Signal ships safety numbers because the platform might one day be compelled or compromised, and the architecture is meant to let you catch that. But almost nobody verifies
We have a solution to this! Wa and Signal both have key transparency. This uses cryptography to make it possible to verify that everyone is getting the same data[1]. Now your phone can check the keys listed under your username are all keys you made (and your contacts can check this too!)
Edit 2 (quick note): if you don't trust the app on your phone to verify your keys, then you also can't trust it to show you a valid security code, or do what the author proposed in their product spaces.
Edit:
It's also striking how similar (in essence) the current solution is to the solution the author is working on/proposing:
> Spaces takes this shape. (Disclosure: I work on it.) Issued names live in a binary Merkle trie. The root of that trie is committed to Bitcoin’s chain, used here as a widely-replicated, hard-to-rewrite timestamp service
Fundamentally the same: the name is your phone number (or alternatively in signal your username), key transparency also uses a merkle tree based structure. Instead of using the bitcoin chain as a consensus mechanism, key transparency implementations generally use trusted witnesses: simple servers that promise to only sign consistent versions of the merkle tree. This is better! Because essentially no clients (phones) have a local copy of the bitcoin chain, so you still have to trust a server to tell you what was posted in the bitcoin block.
For the rest current key transparency systems also have verifiers, which verify that the append only merkle tree is transformed into a dictionary legitimately (this is pretty compute intensive, and needs to be done by a trusted server too. WA currently contracts cloudflare as their only verifier). Spaces would also have to do this to be secure if they reach any scale, but this isn't mentioned in TFA.
Also a message for the author: Key transparency is cool tech, but you shouldn't reinvent the wheel! I hope you research current solutions more! You can ask questions in the transparency.dev slack (https://transparency.dev/slack/)
[1]: There are a bunch of details here. You need to check that everyone _is_ actually getting the same data. There are multiple ways to do this. The transparency ecosystem has generally stabilized on a system where you have trusted verifiers. But anyone (yes you!) can setup a server that can help monitor the chat app and trusted verifiers.
> This is better! Because essentially no clients (phones) have a local copy of the bitcoin chain, so you still have to trust a server to tell you what was posted in the bitcoin block.
Not quite :) also addressed in the post. look at the end of "The CA of all CAs " section.
Happy to share more if anyone is interested in this space: hn@sepositus.com. We're in shadow mode so not much public material at this point (although we do have a full PoC).
Well, there is a LOT of ongoing PGP modernization work on both specifications and implementations in recent years and my team and I at Distrust will be publishing a writeup on it any day now, as well as organizing yet another key generation and signing party in San Francisco next month.
PGP is not going away any time soon, and it is more relevant than ever.
For now check out this post about how we use it to build trust in the Linux ecosystem today: https://kron.fi/en/posts/stagex-web-of-trust/
PGP's "self-sovereignty" comes from mutually agreeing with groups of people who already know each other to exchange files establishing identities. That is to trusted identity what the one time pad is to cryptography: a punt on the entire problem space.
Or between total strangers that met in person at a key signing party and agreed "you look like a human and not a bot to me".
We need human identity to be certified by humans using very long lived standard PKI primitives. Anything else, bots can easily monopolize to the point of being useless.
Rather than debate this here though yet again, I am working on a blog post which includes a lot of quotes, including one from you, to make a case for why PGP is still the best and most widely used and useful proof-of-human and self-sovereign PKI solution that exists, and why we should double down on it.
That comment thread is sure to be interesting.
There are dozens of keys claiming to be Torvalds that lack credible endorsements from high reputation identities, so those are easily ignored. The one that has been signing the Linux kernel for years and signed by many people putting their reputations on the line is the one we care about.
It is intuitive and does not need a math degree to understand.
For me and thousands of other Linux distro maintainers that maintain the core software supply chains and infrastructure that runs the internet, we cannot afford centralized trust graphs. Nothing else comes close to solving the problems PGP solves.
That is why it is an active IETF standard with modern cryptography and several actively maintained and widely used implementations.
Decentralized human trust, or centralized corporate trust. Pick one.
It completely and totally collapses in the face of non-technical users or broad adoption, which is one of multiple reasons that PGP remains a thing that a small set of people use.
I have lost count of the orgs I have personally trained to use PGP properly in recent years.
In spite of your claims, PGP solves the problem it was designed to solve for the groups that need it most and the tooling is getting rapidly more accessible to a wider audience with more development energy today than it has ever had.
This is not 2016 PGP we are talking about anymore.
A renewed IETF working group that aggressively deprecated legacy ciphers and mandated modern ones with optional PQ crypto support (RFC 9580). Lots of actively developed rust implementations like rPGP, rsop, rpgpie, sequioa. Easy key provisioning and backup with smartcard support via keyfork. Smartcards with rust firmware by Nitrokey. Modern key distribution and trust bootstrapping via openpgp-ca, hagrid, keyoxide, etc.
GnuPG is admittedly garbage, but also that has not been a valid implementation of PGP specifications for a while and no one should use it anymore. PGP != GPG
I would strongly suggest taking a hard look at the last decade of thankless work going on to modernize the PGP ecosystem we all rely on directly or indirectly.
Currently writing up the above and a lot more in detail to refute years of outdated rhetoric on this topic so we can start having more useful conversations about it.
Having a bunch of implementations of an omnibus package that tries to be a crypto swiss army knife, written almost exclusively without the input of cryptographers, is actually not a desirable goal.
This fragile network we all use is made of a mountain of pigs that continually need their lipstick reapplied by people that do it for free or near free out of a desire to keep the whole thing running for everyone.
Said people even do it for the users that stay at safe distance pointlessly saying "We should go back in time and build it differently in unspecified ways!".
Or that the replacements being aren’t as concerned as you are with the IETF process?
Yep. I have read every single blog post I can find from critics. Most several times. As have most people that work on this stuff. Some were partly relevant when they were posted and even less relevant today. All of them completely missed the boat on the problems PGP solves that none of the alternative do, or have any serious suggestions for migration paths or standards changes.
I will be quoting most of those posts in a blog post in the next couple weeks on https://distrust.co.
Most of them have corporate alternatives to sell you which have no chance of adoption by standards bodies.
It proposes that dissidents and security researchers from all countries from a wide range of backgrounds and beliefs on privacy, should all just accept the terms of service of their pick of two US based surveillance capitalism mega-corporations, trust they do not have any insiders or vulns, then reveal their identity to cell carriers in most countries, to get signal up and running, whose terms of service they must also accept, and then with the help of two corporations and their proprietary software supply chains, they can then submit an encrypted security vulnerability.
I legitimately laugh every time at the US corpo-brained takes in posts like these.
TL;DR: "Just let the US tech giants handle all identity and communication for the whole internet. What could go wrong? Super secure companies with great uptime like Microsoft GitHub can sign our commits for us and of course Google and Apple pinky swears to disobey executive orders to serve tampered updates of Signal to select devices. It will be fine."
The people that use their PGP keys to sign and securely distribute damn well near every binary that powers the internet are mostly in Europe, and not big fans of letting centralized and mostly proprietary US institutions control their online identity, let alone trusting them to not use a supply chain attack to read their private security correspondence. I for one have found a pile of serious vulns, including in GnuPG, and I do not have a Signal account and never will as I disagreed with the terms of service of Apple Google and Signal. Anyone that does not want plaintext disclosures would be wise to publish PGP keys for people like me. Thankfully most major tech firms still do, even if only to appease non US citizens and my fellow decorpoed americans.
Encrypted email is the only neutral decentralized and IETF standard comms tool we have. I say that as also a big fan of Matrix and would love to see it or something decentralized like it standardized but right now email is the standard so the snowdens and security researchers of the world should use PGP with modern ciphers and learn how to do it offline when doing high risk comms.
Even so, on the other side of this, having setup bug bounty programs for many orgs, the PGP encrypted/signed submissions from reputable folks were always the really spicy shit I would not want anywhere near a modern smartphone, and I would always decrypt them offline with a smartcard for good reason. I would not even consider being party to a bug bounty program that does not publish a PGP key to be maximally inclusive, even if they hate PGP.
Also re tarsnap. It does not even support smartcards, so just shove your private key for your entire filesystem in system memory, and back it up to a conventional password manager I guess? WTF.
Meanwhile with PGP you generate a key on a smartcard, you provide the public key to duplicity, and you can do backups without ever exposing your private key.
The alternatives suggested are strictly worse by any metric, and fail to understand the threat models of existing solutions.
Got it.
If you want to use shiny new ciphers, expect to have limited reach to those on legacy tools. Tradeoffs each user can make for themselves.
That is not an OpenPGP problem, that is just the nature of distributed systems.
Just like IE6, GnuPG abandoned the global standardization processes and in doing so forced an expensive migration to successors.
Global changes on the internet take decades in part because of all the people far removed from the process spreading outdated information and demanding we give up on standards and move the whole world to centralized solutions that do not even solve the same problems, like Java Applets, Adobe Flash, or Signal.
Meanwhile those standardizing and rolling out longer term solutions roll their eyes and keep doing the work.
I'd pose this challenge to you: find the most reputable cryptography engineer or academic cryptographer you can find that believes this is a good idea. I'd be interested if you could find even one. Fair warning: some of my confidence talking down PGP comes from knowing what the conventional wisdom among cryptographers is about the PGP cryptosystem.
If we are going to play the appeal to authority game, I could just as easily challenge you to find any willing to publicly point out any serious issues with the current PQ focused OpenPGP standards with implementations using libraries by accomplished cryptographers. I am sure they would appreciate constructive feedback. Encourage them to join the specification process and recommend specific alternatives and migration paths.
I also wonder if we could find any that would not scrap TLS DNS and a lot of IETF protocols that run the internet today if they could. Decentralized protocols are messy but anything that tries to replace them without first taking the time to understand the current uses and migration path has no hope of success, and that is brutally difficult political work full of careful compromises.
Famous cryptographers have long advocated for things like tcpcrypt, and I even agree with them, but it will probably never happen. Too disruptive. We are still rolling out IPv6 FFS. When faced with an established global internet, compatible lower disruption migration steps are the only way forward as most experienced security engineers would begrudgingly agree.
Cryptographers should absolutely focus on the security of the ciphers, but when it comes to applications, and human privacy and security goals, and human to human trust bootstrapping protocols, the conversation has to get a lot wider. It is normally dominated by security engineers like us close to the hands on use cases, and the people doing the hard work in the working groups and tool development circles that understandably wish to quietly read different takes from a safe distance.
Cryptography basically always explodes at the joinery. One of the guiding principles of modern cryptographic tools is designing implementations that do not have footguns, where the default behavior solves the default threat model and dangerous things are outright impossible. This has been apparent in the string of GPG security failures over the past several years. It's not that somebody breaks RSA or AES. It's that the tools willingly emit bad data because of bad error handling, and then users are told they were holding it wrong and it's their fault for choosing a bad implementation.
Maybe it's worth asking if the reason cryptographers aren't engaging with the work to "modernize" PGP, and that instead we're seeing them building and shipping individual focused solutions to specific workflows, is perhaps because their constructive feedback is akin to ~"you are fundamentally trying to prop up a house of cards that should not exist"
I really hope I am misunderstanding you.
I’m saying several things, but since you’re really focused on Linux package signing, I’m saying about that: PGP is a bunch of theatre there and distros should use minisign instead.
Linux package signing is a great example of where PGP is goofy. Users of Linux distros get their root of trust by downloading a keyring from the exact same place they download the distro ISO. To a rounding error, no users are checking a trust path from them to a distro maintainer, nor does the trust path between one maintainer and another matter.
Distros are themselves centralized entities. They already run bug trackers and forums and centralized package repos that necessitate an authentication system.
So PGP effectively becomes a clunky behemoth whose output is just “every package has a signature that is checked against a centrally curated set of keys that get shipped around to users”.
Moving to minisign would be a strict improvement.
Okay so drop the IETF standard, web of trust, smartcard support, and external key discovery mechanisms to prove the whole keychain was not swapped out with a fake one, and just have everyone generate minisign keys exposed to system memory with no trust link backwards, and then sign things with probably the same algorithms. But then we cannot sign commits or code reviews with minisign because non standard, so i guess use ssh keys for those, and then maintain multiple keychains for each person.
Minisign is strictly worse in every way. Your camp will never convince Linux maintainers to switch with this pitch.
Many of us actually do verify the web of trust, extensively. I have many Linux maintainers in my own keychain independent from their usage in linux distros. Minisign has no such key distribution and accountability system.
Yes, all of that.
I would suggest you pick one of the mainline Linux distros that relies on PGP and make a detailed RFC with a plan to downgrade their security to your non standard minisign/ssh solution with private keys exposed in system memory as you propose, and make a convincing case why it is worth it and what advantages they get for doing so.
Let me know if you do. I am sure it will be a great case study.
OpenBSD does fantastic work, but you and I both know it will never have any significant adoption on the web at this point.
Try to convince an actual Linux distro running any significant portion of the web they should stop using Ed25519 via PGP smartcards and use Ed25519 via signify exposing their keys to system memory (and thus malware) instead, with no key discovery protocol, for unspecified reasons.
Would love to see a threat modeling case for that.
At this point you have shown your hand. You hate PGP so much you would make security for everyone worse to get rid of it. There is no reasonable threat model to support your position.
That said protonmails lead cryptographer has been quite public about his support of the refresh and helping lead some efforts https://proton.me/blog/openpgp-crypto-refresh
I have dozens of more examples of high risk orgs with cryptography teams relying on PGP I am compiling for my post right now. Added a bunch of extra ones just for you.
Honestly from my side of the table, it is the anti-pgp camp that appears to be the loud minority. The world quietly runs on "dead" PGP technology so deeply that any calls for a complete replacement without any compatibility or trust transition path are clearly under-researched and should not be taken seriously.
I have a hard time imagining many cryptographers deeply aware of the impossibility of any rapid transition away from PGP would suggest we abandon the migration to secure modern ciphers now.
A lot of people would like to -eventually- move away from openssl too, myself among them, but not updating to openssl 4 and beyond in the short term would be a world burn kind of move.
Botmasters like situations where they can hide offline and buy bots blue checkmarks with stolen credit cards.
But if you were to actually succeed in making key signing parties a more common thing that people used to test for human-ness, and that test was tied to meaningful things online, it would both become easier to fake and more valuable to fake.
If you look at my key, you will find it is heavily connected to the keys that sign most linux distributions, bitcoin, and commits to the Linux kernel today.
If those 5444 linked identities that long pre-date AI are colluded to create a fake me and fake people that signed people who signed me over the last 25 years, and got those fake fingerprints in the keychains of every distro and got matching fingerprints on thousands of privately owned sites, we indeed have serious problems.
PGP does not need mass adoption to function, but with solutions like keyoxide offering a more accessible trust onramp, it is there for anyone that wants to self certify and take control of their own identity today, and get signed by trusted community members tomorrow at a conference.
Which bit of PGP?
Which is the thing, we do need a single key that can be used for all those things. So we get PGP.
I thought everyone was "trying so hard to re-invent PGP".
> we do need a single key that can be used for all those things
We do? This is not obvious. Why does my disk encryption key need to be the same that I use to sign binaries that I release?
PGP keychains allow you to have a single 24 word mnemonic seed to recover your entire digital identity, data access, etc. The UX is strictly better than the commonly suggested hodge podge of flavor of the week alternatives.
Standards make interoperability a lot easier.
1. You reveal your social graph
2. Different instances of the key can be differently signed
For someone to sign your key that information has to be stored on your key or in a central location.
I don't know if anyone has actually done this in practice. Does it work?
It is pretty useful for someone totally outside the trust graph to be able to prove the key that just signed the latest release of stagex is only a couple steps away from the keys that sign debian and the Linux kernel. Keys that long predate AI.
Public trust accountability is exactly what we want from people responsible for the legos that make up the internet.
You can of course have private signature packets revealed as needed though.
> "Supply is capped at about ten per day. Individual squatting (buy at auction, hold, resell) is possible. "
Won't this mean that squatters will keep buying the top-alexa domains for the first few years?
I'd have liked to see a comparision with other "crypto"-led infra in this space. .eth/ENS, namecoin, .box, .bit for eg.
this article shows "alice@key" which looks very sensible.
then one click away, joining spaces, you can only get "horse-battery-staple@key AGE age1hsuwgduwhdiehhduwhdiheudhwi..."
and one cannot even pick the first part! pure insanity!
Why write in such a silly way? Do you mean "Spaces does this"?
Take my money.
(Care of randomly shuffled https://spacesprotocol.org/faucet/)
We do, you just don't know about:)
SDK: https://github.com/CipherTrustee/certisfy-js
Web trust use: https://bsky.app/profile/bitlooter.bsky.social
Some examples of how you could leverage it: https://blog.certisfy.com/
Happy to answer questions.