Show HN: Send encrypted secrets from the command line | Hacker News Reader

Show HN: Send encrypted secrets from the command line

fluidkeys.com

117 pointspaulfurley42 comments

The tool for this that everyone I know uses is Magic Wormhole. Wormhole has a more straightforward security model and is more thoughtfully designed: it uses a PAKE and relies on out-of-band secret sharing, rather than attempting a registry of "verified" public keys.

You should probably just use Wormhole.

    pip install magic-wormhole

Isn't there only 65K passwords/magic keywords in wormhole ? What if someone constantly bruteforce all of these combinations, wouldn't he get access to the files that you are sending ?

The short answer is that PAKE is single-use, so the attacker only gets one guess (and their attempt prevents the legitimate peer from trying either). Each time they consume someone else's transfer attempt, they get a 1-in-65k chance of succeeding, and a 65535-in-65536 chance of alerting the peer that they failed.

For the attacker to have a 50/50 chance of successfully stealing your file transfer, you'd have to (on average) re-run the `wormhole send` program over 30000 times. I don't know about you, but I'm not that patient, and I'd give up long before they had a significant chance of success :).

This is covered in their docs, along with mitigation.

https://magic-wormhole.readthedocs.io/en/latest/attacks.html

That's cool, and I'm going to give it a go: thanks for raising it.

> The two endpoints are identified by using identical "wormhole codes": in general, the sending machine generates and displays the code, which must then be typed into the receiving machine. > The codes are short and human-pronounceable, using a phonetically-distinct wordlist. The receiving side offers tab-completion on the codewords, so usually only a few characters must be typed. Wormhole codes are single-use and do not need to be memorized.

I love that they've put some thought into usability here: that's nice.

BTW it's been in debian+ubuntu for a couple of years, so `apt install magic-wormhole` works too.

I made something similar, but the payload gets encrypted with the users ssh rsa key instead of pgp (that not many use):

  ./sshencdec.sh -p <(curl -sf "https://github.com/S2-.keys" | \

  grep ssh-rsa | tail -n1) < plain-text-file.txt

It's just a simple bash script really, but it works, and almost everyone has a github account and an ssh key set up, so it works out of the box with most developers.

https://github.com/S2-/sshencdec

That's cool!

We were doing similar things ourselves with GPG. But ultimately we'd forget the exact command, or the copy-pasting in then out of Slack was enough of a barrier that we'd basically never bother.

Curious how such a small barrier was a blocker. Our hypothesis is that, if we can make `fk secret send` easier than literally everything else, people will default to it, and it'll be a win for security. We shall see!

To be honest this just seems like an insecure version of Keybase.

The key thing with Keybase is that it cryptographically verifies your public keys against public statements published to accounts people know you by - eg your Twitter, Facebook, etc.

The difficult bit isn't encrypting and sending. The difficult bit is the original key exchange. Keybase has dealt with this without you having to trust Keybase itself.

> Fluidkeys automatically fetches keys based on the verified email address and encrypts the secret to the key.

Fetches from where? Public key servers?

Anybody can upload a key for you@your-company.com to a public key server.

> We use our own server to store public keys and transmit encrypted secrets.

> We chose not to use the public keyserver network until it supports deleting keys and cryptographic validation.

... as well as the fact that there's no email validation, yep!

They should add support for the OpenPGP Web Key Directory [1] system. Briefly, the idea is that the public key for user@example.com should be available at https://example.com/openpgp/hu/<blah> where <blah> is generated as described in the document.

Gpg supports looking up keys via this since 2.1.12 [2]. An example of how to lookup and get a key this way can be seen here [3].

[1] https://tools.ietf.org/html/draft-koch-openpgp-webkey-servic...

[2] https://wiki.gnupg.org/WKD

[3] https://lists.gnupg.org/pipermail/gnupg-devel/2018-June/0338...

Yes! We're working on it, both client side and server side.

We've got WKD working on our own hello@fluidkeys.com email address using a rather cheeky hack[1].

Server side, we're adding this to Fluidkeys Server soon.

That way, teams that use Fluidkeys could redirect `<team-domain>/.well-known/openpgpkey/(.*)$` to our server, and voila, we'll serve their keys via WKD

[1]: https://github.com/fluidkeys/web-key-directory/

I was just going to ask the same question about WKD support. Having control over key distribution in an organization is a very important factor for me.

This is a clever idea. Unfortunately, it doesn't seem like most mail providers would store something like this.

I can't see Gmail doing it :)

But mostly teams control their own mail domain, so they can do what they like (for example, use Fluidkeys, and we'll do WKD for them!)

Nice to see more solutions like these pop up.

Another great one is Magic Wormhole, which uses a parallel human-to-human channel to negotiate a secure machine-to-machine exchange:

https://github.com/warner/magic-wormhole

I've been using Magic Wormhole for all my peer-to-peer file transfers and love it.

Who runs the rendezvous server for MW?

(author of magic-wormhole here)

I do. You can use your own, but then both sides have to type in the same --relay-url=URL value (instead of using the one that's baked into the app).

magic-wormhole is both a file-transfer tool and a library for provisioning/transferring secrets via a code. If you were embedding the library in your own app, you might want to bake in a different relay server (which you run) to avoid depending upon me for your uptime.

> The wormhole library requires a “Rendezvous Server”: a simple WebSocket-based relay that delivers messages from one client to another. This allows the wormhole codes to omit IP addresses and port numbers. The URL of a public server is baked into the library for use as a default, and will be freely available until volume or abuse makes it infeasible to support. Applications which desire more reliability can easily run their own relay and configure their clients to use it instead. Code for the Rendezvous Server is included in the library. (o)

notably, you can run your own

(o) https://magic-wormhole.readthedocs.io/en/latest/welcome.html...

Look here:

https://magic-wormhole.readthedocs.io/en/latest/welcome.html...

tl,dr:

- Rendezvous server is a public one - You can run your own - Code is in the `wormhole` library.

Ooh this looks awesome, thanks for sharing.

I can see the attraction of the automation. We happen to use a simple script that builds a self-extracting shell script. Like (passphrase is 123):

  #!/bin/sh
  gpg -d <<EOF
  -----BEGIN PGP MESSAGE-----
  jA0ECQMCnEJkjjuJ64/j0kYB4JiTGPazY81ZOn3Ph+zRRnXdtuqB3POPizEykpiZ
  CT8p5SiJfXQagTLUCDpR3VCicPw4QirQoOhkLqmzRXS4EBPjkTla
  =+soW
  -----END PGP MESSAGE-----
  EOF

Then the receiver doesn't have to remember any commands.

How does this compare to keybase?

I'm a user but no expert about keybase. As far as I can tell they've pivoted to taking on Slack & friends with zero-knowledge team-chat, but global. Good luck to them!

We're not in a hurry to try and move people off Slack or GnuPG: teams have their existing services (Slack, G-suite) and other workflows like Thunderbird + Enigmail, git signing etc. We think complementing those existing flows is the way to go.

The longer term vision is that your team can sign up to Fluidkeys, download it and it sets up everyone's email client, git, pass etc according to your team's configuration. Then it quietly keeps everyone's keys updated when people join and leave the team. (and we rotate encryption subkeys every month)

Back to today: 0.3's sending secrets feature is a small diversion from that goal, but we hope a useful feature in its own right :)

I'd love your feedback on the vision above!

> As far as I can tell they've pivoted to taking on Slack & friends with zero-knowledge team-chat, but global.

What? I'm pretty curious what gave you this impression, as I've always seen their chat app as an interesting use built on top of their encrypted file system work, but in no way their primary use-case or business.

We (and everyone else I know that uses Keybase) use it for passing around sensitive information, either through chat, their encrypted Git repos, encrypted messages plopped into emails, etc.

I think Fluidkeys is cool and all, but I definitely wouldn't switch off of Keybase for it, and I think you're doing yourself a disservice by pretending that Keybase is "just another chat app" now and not a direct competitor that also has secure communication built in.

Thanks for pushing back on this.

> We (and everyone else I know that uses Keybase) use it for passing around sensitive information, either through chat, their encrypted Git repos, encrypted messages plopped into emails, etc.

That is interesting. I'm gonna put my hand up and admit I haven't done my homework here. It's been a while since I used it properly and I've relied too heavily on their website:

> Keybase is for anyone. Imagine a Slack for the whole world, except end-to-end encrypted across all your devices. Or a Team Dropbox where the server can't leak your files or be hacked.

> I think Fluidkeys is cool and all, but I definitely wouldn't switch off of Keybase for it,

Thanks, and I wouldn't expect you to have to switch. We're gonna think properly about where we're competing. I appreciate your input.

I guess they are solving similar problem, but this is automatically sending the email to the recipient. Also the integration with GPG may be preferable to some people if they don't have an extensive community of Keybase peers.

Also had the same question. :)

Nicely done. One nitpick would be that initial peer key discovery looks a bit iffy. Do I understand correctly that fk fetches it from a key registry that is hosted by you?

Is a self-hosted version of the same possible?

Additionally, there should probably be

a) Some sort of "paranoid" mode whereby it would show me peer's key (in some form) so that I could, if really wanted, manually verify it.

b) An option to cache peer keys locally. I assume this is done already and that the local cache lookup is given a priority over the registry search. Correct?

Thanks!

Yes, we're currently hosting public keys.

> Is a self-hosted version of the same possible?

The honest answer is, we're not sure yet. It's our strong ambition to make Fluidkeys into an honest, you're-the-customer business, and we aren't sure how we'll license the server. Is self-hosting something your team would be willing to pay for? If so, that might help our business model development! :)

> a) Some sort of "paranoid" mode whereby it would show me peer's key (in some form) so that I could, if really wanted, manually verify it.

This is a great idea. In that mode, it could output the key fingerprint and prompt before sending. Would that work for you?

> b) An option to cache peer keys locally. I assume this is done already and that the local cache lookup is given a priority over the registry search. Correct?

Not yet, mostly for simplicity of getting this release shipped. It's currently pretty naive (and I'm not thrilled about it): the key lookup API call is done every time you send a secret. Thinking of fimiliar patterns, perhaps we should take the SSH trust-on-first-use approach, where we record the fingerprint we saw last time, and warn if it changes? That would make it significantly harder for us to subsequently serve you bad keys.

Somewhat related, there was a good discussion about how to deal with multiple key discovery mechanisms (e.g. local cache vs server response) at the latest OpenPGP summit. Prioritising local cache (say, your GnuPG keyring) can be quite scary too, if you downloaded a key from the keyservers and subsequently realised it was a fake (and don't use web-of-trust which, well, enough said).

Thanks for thinking about this and taking the time to share your ideas.

> It's our strong ambition to make Fluidkeys into an honest, you're-the-customer business

Without sugar-coating it - a service like this, with the scope it has now, has * zero * chance of successful monetization. 100% guaranteed.

This is a cosmetic service that aims to address a security need. People who actually need this AND have money to pay for it are in position to explore self-hosted options, which is what they will be looking for in the first place since they DO want proper security. Having a random third party in their security pipeline is not really an option. And people who are not concerned with this part, won't think twice about sending API keys over regular email. In fact, even security-minded people won't have much objection to relaying secrets through their corporate, properly secured email server.

Then, there's an option of productized (self-hosted) version. This is not likely to work either, because the whole thing looks rather trivial and, put bluntly, not worth paying for. Like you aren't likely to pay for hugs, no matter how good they are. Same here - nice to have, but only if free.

All that said, the website is nicely designed and the whole thing is well-presented. It certainly has a potential to be a good demo/promo piece for something larger.

That's a thoughtful analysis, thanks. I appreciate the lack of sugar coating :)

Do the messages automatically get wiped? Typically you don't want to keep the keys in your message boxes in case they get hacked in the future.

For this reason I use something like read then burn[1,2] for passwords.

[1] https://readthenburn.fnkr.net/ [2] https://github.com/Tethik/burn-after-reading

They do, when you receive messages you're prompted to delete them, with a default of "yes". And we're careful for the secrets not to end up in any log files either.

Setup is nice ... just sent a message to the Squirrel. ;-)

Don't have much time now but just wanted to give this a quick +1, worth checking out.

Thanks for the kind words, and for the message ;)

Or use Piknik: https://github.com/jedisct1/piknik

On a side note, PSA: do not commit your AWS keys into github. Also, now you have the ability to make your repos private. Head over and do it now.

Ha! Yeah. I must admit I've accidentally committed a Github access token before. It was in a `secrets.sh` file which I mistakenly thought was in `.gitignore` and carelessly added to a WIP commit.

Github was amazing, they detected it, saw that it was valid, and revoked the token. Big love.

On private repos: it would be a sad, sad thing if all those half-baked pet projects went away, there's an awful lot of valuable random stuff in public repos.

Also PSA: if you ever decide to make said repo public, `git push --force` does not make the old commits unaccessible; doing so is not a secure way to remove secrets from a git remote before making it public

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