Keysafe securely backs up a gpg secret key or other short secret to the cloud. But not yet. Today's alpha release only supports storing the data locally, and I still need to finish tuning the argon2 hash difficulties with modern hardware. Other than that, I'm fairly happy with how it's turned out.
Keysafe is written in Haskell, and many of the data types in it keep track of the estimated CPU time needed to create, decrypt, and brute-force them. Running that through a AWS SPOT pricing cost model lets keysafe estimate how much an attacker would need to spend to crack your password.
(Above is for the password "makesad spindle stick")
If you'd like to be an early adopter, install it like this:
sudo apt-get install haskell-stack libreadline-dev libargon2-0-dev zenity stack install keysafe
~/.local/bin/keysafe --backup --store-local to back up a gpg key
I still need to tune the argon2 hash difficulty, and I need benchmark data to do so. If you have a top of the line laptop or server class machine that's less than a year old, send me a benchmark:
~/.local/bin/keysafe --benchmark | mail email@example.com -s benchmark
Bonus announcement: http://hackage.haskell.org/package/zxcvbn-c/ is my quick Haskell interface to the C version of the zxcvbn password strength estimation library.
PS: Past 50% of my goal on Patreon!
Have you ever thought about using a gpg key to encrypt something, but didn't due to worries that you'd eventually lose the secret key? Or maybe you did use a gpg key to encrypt something and lost the key. There are nice tools like paperkey to back up gpg keys, but they require things like printers, and a secure place to store the backups.
I feel that simple backup and restore of gpg keys (and encryption keys generally) is keeping some users from using gpg. If there was a nice automated solution for that, distributions could come preconfigured to generate encryption keys and use them for backups etc. I know this is a missing peice in the git-annex assistant, which makes it easy to generate a gpg key to encrypt your data, but can't help you back up the secret key.
So, I'm thinking about storing secret keys in the cloud. Which seems scary to me, since when I was a Debian Developer, my gpg key could have been used to compromise millions of systems. But this is not about developers, it's about users, and so trading off some security for some ease of use may be appropriate. Especially since the alternative is no security. I know that some folks back up their gpg keys in the cloud using DropBox.. We can do better.
I've thought up a design for this, called keysafe. The synopsis of how it works is:
The secret key is split into three shards, and each is uploaded to a server run by a different entity. Any two of the shards are sufficient to recover the original key. So any one server can go down and you can still recover the key.
A password is used to encrypt the key. For the servers to access your key, two of them need to collude together, and they then have to brute force the password. The design of keysafe makes brute forcing extra difficult by making it hard to know which shards belong to you.
Indeed the more people that use keysafe, the harder it becomes to brute-force anyone's key!
I could really use some additional reviews and feedback on the design by experts.
I've been funded for two years by the DataLad project to work on git-annex. This has been a super excellent gig; they provided funding and feedback on ways git-annex could be improved, and I had a large amount of flexability to decide what to work on in git-annex. Also plenty of spare time to work on new projects like propellor, concurrent-output, and scroll. It was an awesome way to spend the last two years of my twenty years of free software.
That funding is running out. I'd like to continue this great streak of working on the free software projects that are important to me. I'd normally dip into my savings at this point and keep on going until some other source of funding turned up. But, my savings are about to be obliterated, since I'm buying the place where I've had so much success working distraction-free.
So, I've started a Patreon page to fund my ongoing work. Please check it out and contribute if you want to.
Some details about projects I want to work on this fall:
PocketCHIP is the pocket sized Linux terminal I always used to want. Which is to say, it runs (nearly) stock Debian, X, etc, it has a physical keyboard, and the hardware and software is (nearly) non-proprietary and very hackable. Best of all, it's fun and it encourages playful learning.
It's also clunky and flawed and constructed out of cheap components. This keeps it from being something I'd actually carry around in my pocket and use regularly. The smart thing they've done though is embrace these limitations, targeting it at the hobbiest, and not trying to compete with smart phones. The PocketCHIP is its own little device in its own little niche.
Unless you're into hardware hacking and want to hook wires up to the GPIO pins, the best hardware feature is the complete keyboard, with even Escape and Control and arrow keys. You can ssh around and run vi on it, run your favorite REPL (I use ghci) to do quick programming, etc. The keyboard is small and a little strange, but you get used to it quickly; your QWERTY muscle memory is transferrable to it. I had fun installing nethack on it and handing it to my sister who had never played nethack before, to watch her learn to play.
The screen resolution is 480x272, which is pretty tiny. And, it's a cheap resistive touchscreen, with a bezil around it. This makes it very hard to use scroll bars and icons near the edge of the screen. The customized interface that ships with it avoids these problems, and so I've been using that for now. When I have time, I plan to put a fullscreen window manager on it, and write a pdmenu menu configuration for it, so everything can be driven using the keyboard.
I also have not installed Debian from scratch on it yet. This would be tricky because it uses a somewhat patched kernel (to support the display and wifi). The shipped distribution is sadly not entirely free software. There are some nonfree drivers and firmwares. And, they included a non-free gaming environment on it (a very nice one for part of the audience, that allows editing the games, but non-free nevertheless). They did do a good job of packaging up all the custom software they include on it, although they don't seem to have published source packages for everything.
(They might be infringing my GPL copyright of flash-kernel by distributing a modified version without source. I say "might" because flash-kernel is a pile of shell scripts, so you could probably extract the (probably trivial) modifications. Still.. Also, they seem to have patched network-manager in some way and I wasn't able to find the corresponding source.)
The battery life is around 5 hours. Unfortunately the "sleep" mode only turns off the backlight and maybe wifi, and leaves the rest of the system running. This and the slightly awkward form factor too big to really comfortably fit in a pocket limit the use of PocketCHIP quite a bit. Perhaps the sleeping will get sorted out, and perhaps I'll delete the GPIO breakout board from the top of mine to make it more pocket sized.
I write free software and I have some users. My primary support channels are over email and IRC, which means I do not have direct access to the system where my software runs. When one of my users has a problem, we go through one or more cycles of them reporting what they see and me asking them for more information, or asking them to try this thing or that thing and report results. This can be quite frustrating.
I want, nay, need to improve this.
This is also something I've thought about on and off, that affects me most every day.
I've found that building the test suite into the program, such that
users can run it at any time, is a great way to smoke out problems. If a
user thinks they have problem A but the test suite explodes, or
also turns up problems B C D, then I have much more than the user's
problem report to go on.
git annex test is a good example of this.
Asking users to provide a recipe to reproduce the bug is very helpful; I do it in the git-annex bug report template, and while not all users do, and users often provide a reproducion recipe that doesn't quite work, it's great in triage to be able to try a set of steps without thinking much and see if you can reproduce the bug. So I tend to look at such bug reports first, and solve them more quickly, which tends towards a virtuous cycle.
I've noticed that reams of debugging output, logs, test suite failures, etc can be useful once I'm well into tracking a problem down. But during triage, they make it harder to understand what the problem actually is. Information overload. Being able to reproduce the problem myself is far more valuable than this stuff.
I've noticed that once I am in a position to run some commands in the environment that has the problem, it seems to be much easier to solve it than when I'm trying to get the user to debug it remotely. This must be partly psychological?
Partly, I think that the feeling of being at a remove from the system, makes it harder to think of what to do. And then there are the times where the user pastes some output of running some commands and I mentally skip right over an important part of it. Because I didn't think to run one of the commands myself.
I wonder if it would be helpful to have a kind of ssh equivilant, where
all commands get vetted by the remote user before being run on their
system. (And the user can also see command output before it gets
sent back, to NACK sending of personal information.)
So, it looks and feels a lot like you're in a mosh session to the user's
computer (which need not have a public IP or have an open ssh port at all),
although one with a lot of lag and where
rm -rf / doesn't go through.
This series has focused on new projects. I could have said more about
significant work that didn't involve starting new projects. A big example was
when I added
dh to debhelper, which led to changes in a large
debian/rules files. And I've contributed to many other free
I guess I've focused on new projects becuase it's easier to remember things I've started myself. And because a new project is more wide open, with more scope for interesting ideas, especially when it's free software being created just because I want to, with no expectations of success.
But starting lots of your own projects also makes you responsible for maintaining a lot of stuff. Ten years ago I had dozens of projects that I'd started and was still maintaining. Over time I started pulling away from Debian, with active projects increasingly not connected with it. By the end, I'd left and stopped working on the old projects. Nearly everything from my first decade in free software was passed on to new maintainers. It's good to get out from under old projects and concentrate on new things.
I saved propellor for last in this series, because I think it may point toward the future of my software. While git-annex was the project that taught me Haskell, propellor's design is much more deeply influenced by the Haskell viewpoint.
Absorbing that viewpoint has itself been a big undertaking for me this decade. It's like I was coasting along feeling at the top of my game and wham got hit by the type theory bus. And now I see that I was stuck in a rut before, and begin to get a feeling of many new possibilities.
That's a good feeling to have, twenty years in.
Propellor is my second big Haskell program. I recently described the motivation for it like this, in a proposal for a Linux.Conf.Au talk:
The configuration of Linux hosts has become increasingly declarative, managed by tools like puppet and ansible, or by the composition of containers. But if a server is a collection of declarative properties, how do you make sure that changes to that configuration make sense? You can test them, but eventually it's 3 AM and you have an emergency fix that needs to go live immediately.
Data types to the rescue! While data types are usually used to prevent eg, combining an Int and a Bool, they can be used at a much more abstract level, for example to prevent combining a property that needs a Debian system with a property that needs a Red Hat system.
Propellor leverages Haskell's type system to prove the consistency of the properties it will apply to a host.
The real origin story though, is that I wanted to finally start using configuration management, but the tools for it all seemed very complicated and built on shaky foundations (like piles of yaml), and it seemed it would be easier to write my own than deal with that. Meanwhile, I had Haskell burning a hole in my pocket, ready to be used in a second large project after git-annex.
Propellor has averaged around 2.5 contributions per month from users since it got started, but increasing numbers recently. That's despite having many fewer users than git-annex, which remember gets perhaps 1 patch per month.
Of course, I've "cheated" by making sure that propellor's users know Haskell, or are willing to learn some. And, propellor is very compositional; adding a new property to it is not likely to be complicated by any of the existing code. So it's easy to extend, if you're able to use it.
At this point propellor has a small community of regular contributors, and I spend some pleasant weekend afternoons reviewing and merging their work.
Much of my best work on propellor has involved keeping the behavior of the program the same while making its types better, to prevent mistakes. Propellor's core data types have evolved much more than in any program I worked on before. That's exciting!
concurrent-output is a more meaty Haskell library than the ones I've covered so far. Its interface is simple, but there's a lot of complexity under the hood. Things like optimised console updates, ANSI escape sequence parsing, and transparent paging of buffers to disk.
It developed out of needing to display multiple progress bars on the console in git-annex, and also turned out to be useful in propellor. And since it solves a general problem, other haskell programs are moving toward using it, like shake and stack.
shell-monad is a small project, done over a couple days and not needing many changes since, but I'm covering it separately because it was a bit of a milestone for me.
As I learned Haskell, I noticed that the libraries were excellent and did things to guide their users that libraries in other languages don't do. Starting with using types and EDSLs and carefully constrained interfaces, but going well beyond that, as far as applying category theory. Using these libraries push you toward good solutions.
shell-monad was a first attempt at building such a library. The shell script it generates should always be syntactically valid, and never forgets to quote a shell variable. That's only the basics. It goes further by making it impossible to typo the name of a shell variable or shell function. And it uses phantom types so that the Haskell type checker can check the types of shell variables and functions match up.
So I think shell-monad is pretty neat, and I certianly learned a lot about writing Haskell libraries making it. Including how much I still have to learn!
I have not used shell-monad much, but keep meaning to make propellor and git-annex use it for some of their shell script needs. And ponder porting etckeeper to generate its shell scripts using it.
ey dad sometimes asks when I'll finish git-annex. The answer is "I don't know" because software like that doesn't have a defined end point; it grows and changes in response to how people use it and how the wider ecosystem develops.
But other software has a well-defined end point and can be finished. Some of my smaller projects that are more or less done include electrum-mnemonic, brainfuck-monad, scroll, yesod-lucid haskell-mountpoints.
Studies of free software projects have found that the average free software project was written entirely by one developer, is not very large, and is not being updated. That's often taken to mean it's a failed or dead project. But all the projects above look that way, and are not failures, or dead.
It's good to actually finish some software once in a while!