Protecting SSH Keys with macOS Secure Enclave | Hacker News Reader

Protecting SSH Keys with macOS Secure Enclave

gatezh.com

384 pointsjs2136 comments

Security features like this works, until it doesn't.

When I installed WireGuard on macOS, I was happy to discover that it stores private keys in the system keychain. Accessing the private key requires Touch ID.

Then one day after a system upgrade, the WireGuard app crashed on startup with:

  [APP] Unable to open config from keychain: -25300

Then the app deleted all profiles because they are all "orphaned", apparently for "keychain consistency" [0].

From then on, I just use a text editor to edit my WireGuard configuration files, and import them to the app. The bug still exists to this day [1].

[0] https://github.com/WireGuard/wireguard-apple/commit/dfb685f2...

[1] https://www.reddit.com/r/WireGuard/comments/wyt828/osx_wireg...

Developing for macos, I’ve gotten bit by keychain consistency issues far too many times. It’s a mess.

So many of the keychain APIs are "deprecated" (read: marked as "we will nuke this API whenever we want") and have been for a decade or more, but have no replacement either.

A lot of the Security Framework came from Classic, hell, the idea of a keychain came from Classic! Just a mess.

Can echo this, I've also fallen foul of keychain behaviour. In my case I found a lookup that passed the account name as raw bytes instead of text didn't match my item. On macOS it matched all items with a blank account (strictly, generic password items), which on my computer meant items from GitHub CLI, Malwarebytes, and Adobe Creative Cloud. The app I was building silently used one of those as its key, and would change whenever one of those apps would update its entry. The fix was to make sure the account is passed as a string and that it has a service name so that lookup either matches exactly my item or none. The API takes a loosely typed dictionary, so wrong types throw no errors, just different behaviour. I now always test against the real keychain and not a mock.

> The bug still exists to this day

You linked a commit and a Reddit post. Is there a proper Github issue as well?

from his link:

  Edit (March 2025):
  Wireguard, to my surprise, has no bug tracking system like Jira or issue tracking area such as GitHub.
  If you want to see this fixed, the only way to instigate change is to write team@wireguard.com and jason@zx2c4.com.

> You linked a commit and a Reddit post. Is there a proper Github issue as well?

It's funny you mentioned that. The GitHub repository is a mirror of https://git.zx2c4.com/wireguard-apple. You cannot create issues there. You're supposed to send a bug report to the mailing list, which is enough friction that none of us did so far.

>enough friction that none of us did so far.

Emailed per https://news.ycombinator.com/item?id=50450200

Definitely still a bug right? Linked them to your parent comment.

Edit: oops sorry team, think you're on it (4d ago): https://github.com/whyredfire/wireguard-apple/commit/0bac142...

Guess it can serve as feedback on the friction when issues can't simply be opened though!

> Definitely still a bug right? Linked them to your parent comment.

Thanks! Yes, it is still a bug.

> Edit: oops sorry team, think you're on it (4d ago)

I don't think @zx2c4 has seen this PR, and the author of the PR has not sent a bug report yet, so it's probably fine :P

All right! :)

> Thanks! Yes, it is still a bug.

Its unfortunate no updates for Wireguard macOS have been pushed out for 3 years, App Store is still showing 1.0.16 as the latest version – as also confirmed on the Wireguard website at the latest version.

No doubt macOS APIs have moved on a lot in 3 years and so perhaps bugs that are being seen are simply a reflection of the lack of updates to keep up with API changes ? Just thinking aloud here, I don't know if the concept of OS API changes are applicable to this particular PR / bug.

>friction

I appreciate when both options exist, because I've passed on reporting so many bugs, because I refuse to create a Microsoft account to do it.

In fact, I don't understand how sending an email is high friction.

> I've passed on reporting so many bugs, because I refuse to create a Microsoft account to do it.

99% of the time it's perfectly fine to just email the maintainer with a bug report and maybe a patch.

> In fact, I don't understand how sending an email is high friction.

Judging from the fact that after so many years, such a widespread (as seen in the Reddit post and here) issue still hasn't resulted in a single bug report in the mailing list, I'd say most people (including myself) do indeed consider using a mailing list to be higher friction.

If I'm not mistaken, unless you're already CC'ed by a participant, you'd have to subscribe to the whole mailing list just to receive notifications for a single thread. For an "issue" on a Git forge, participation is usually as easy as upvoting and then clicking the "Subscribe" button.

Assuming you're already using MS Github. Anyway, even if I was, a lot of Github project require filling out an absurd Simon Says form. Or that scene from Indiana Jones where he takes a wrong step and falls through the floor. That's nothing to do with email or Microsoft specifically, it's just another reason I almost never bother reporting bugs. Talk about friction.

Yeah, I hate these forms (issue templates) too. Every time I have to fill such a form, I always feel that they are discouraging me from writing the bug description in a natural, coherent way. I'd spend more effort to make sure the description is clear and contains all necessary information, if there's no issue template requirements.

Yes, but most people won't. Most people will submit a bug report with important information missing that means we have to go back and forth. Also, there is often specific debugging information that people would not even know would be useful.

In the current age, its useful because AI will submit tickets using the CLI that don't use the form, so I can immediately close and lock them and go on living my life.

"MS Github"(?) is just "Github". They bought it, they own it.

I had this as well - funny enough I asked my local AI to "find the removed config" and it was able to restore everything.

Lucky for you! I first ran into this before AI agents were a thing, so :(

There are features built for security nerds (like PGP/GPG, etc)

And features built for normal people

The overlap is very rare

well but deletion isn't what even those "security nerds" would have expected...

Security nerd here. I would have expected it. But only in the sense that I have no faith in this industry to write secure software and protect from data loss.

I keep hoping better liability laws will force management to support doing it the right way, if not anything else than avoid hefty fines.

This is not a feature built for security nerds. This is a feature built for corporate compliance box tickers, and it works precisely as wanted in corporate environments, where all lost secrets can be easily replaced after visiting the helpdesk room personally.

True, there's that as well

The worst part: the people that work at your bank and at city hall are not security nerds, and don't care to become security nerds. do with that what you will.

I'm using WireGuard myself. Not on MacOS, but on Windows/Linux/Android. The reason I went with WireGuard to begin with, is due to how secure it suppsedly was. Having long standing unresolved issues like that is a bit worrying. I'm still most likely safe, but it's not exactly reassuring, either

This is likely just that if someone chooses an OS that requires a special HW just to build a release with no easy cross-compilation possible, and to pay a gatekeeper just to publish it, and that can't even run on an emulated computer properly, they can't expect FOSS maintainers will be bothered with much more than "here's a source code, build it/test it/do QA yourself if you like" for their particular pet platform.

For platforms where development is unhindered by arbitrary obstacles like these and others, wireguard works fine. :)

Best common on HN this week.

Just going to reply to your comment here: the choice to use wireguard shouldn't come down to relative security (although I guess it gets a benefit here), but from being fast and simplistic.

All of the traditional components of VPN management are removed from the core code. Wireguard follows the model "do one thing, and do it well." It's also built into the kernel, which inherently can make it faster than userland VPN software.

This is why companies like Tailscale exist--as they're basically selling back the features that you would get in a more traditional IPSEC VPN, but in front of Wireguard instead.

This literally just happened to me yesterday. Again.

I’ve been a happy user of Secretive for years, including for Git commit signature which it make it a separate key with interaction but not for pull / push. I find the trade off ideal for GitHub.com and have other keys with different setup for servers.

SSH keys in plaintext was one of the first thing that bagel [0] our developer endpoint secret detection focused on. Then we embedded bagel as a library in our developer endpoint protection [1].

[0] https://boostsecurityio.github.io/bagel/ [1] https://boostsecurityio.github.io/dazio/docs/install/

One fundamental problem with agentic development is that accessing the secure enclave key requires human presence. If you're running headless and aren't logged in, Secretive (not sure about others) will not be able to access the enclave, even when you only chose "notify" and not "touchid".

This is why I'm skeptical that the approach can scale reliably, even though I'm relying on it today. (Yes, PATs would fix this, but the enclave model is what I'm trying to retain for now.) What I've done instead is wrote a small daemon that sets the SSH authentication socket and does agent forwarding. This works when I'm traveling with laptop...but not yet from my mobile phone.

Example:

    Laptop                                   Remote Mac
   ┌─────────────────────┐                  ┌──────────────────────────┐
   │ Secretive           │                  │ ssh / git commit -S      │
   │ (Secure Enclave)    │                  │          │               │
   │        ▲            │  ForwardAgent    │          ▼               │
   │        └── ssh ─────┼─────────────────►│  ~/.ssh/agent.sock       │
   │                     │                  │  (stable proxy)          │
   └─────────────────────┘                  │      │          │        │
                                            │      ▼          ▼        │
                                            │  forwarded   local       │
                                            │  laptop      Secretive   │
                                            │  agent       (if you sit │
                                            │              at this Mac)│
                                            └──────────────────────────┘

NB: I'm not using Rex instead of herdr and because Rex uses its own protocol, I always need to have one SSH tunnel to reset the remote agent socket. Not optimal, but it works. All of this feels wrong from a UX perspective, and it feels like I'm holding on too hard on secure enclave for what my use cases are. Feedback appreciated!

I got a similar idea recently. I was becoming annoyed with the coding agent, running on my laptop, being unable to use sudo (with my supervision) when ssh-ing to my remote server. I wanted to build this as a PAM module. I started building this but after a while I googled (well… asked an agent) a bit more and found out that it already exists: https://github.com/z4yx/pam_rssh

I’m a happy user!

Two thoughts on this:

1. The Secure Enclave being inaccessible when you're not present is a feature, not a bug. If you need to run headless then its not the correct solution to your problem and you'll have to find another.

2. You don't need an SSH agent proxy, you can use a `match` block in your `ssh_config` with something like `host * exec "test -z $SSH_TTY` to check whether you're operating over an SSH connection and select Secretive's SSH agent if you're using the machine locally.

Not sure how it works on macos, but on Windows the downside of agents using TPM backed Windows Hello keys (sk) is that the session can't be reused for scp/sftp and agents like to do one-action scripts, so you're doing the user presence pin/finger multiple times for each ssh command it executes.

I've started building a timeout-based ssh-agent population utility, but if I'm honest, TPM keys without user presence is probably sufficient.

> requires human presence

I'm not using the secure enclave, but I've been using YubiKeys for many years, and now that AI has arrived, I consider the above to be a good thing.

This means, for example, that unless I am physically present with my key inserted, activated, and touched on every operation, an AI agent cannot access any of my production servers. As I do not want AI agents to access my production servers, this is a very good protection technique. I am assuming that no matter how well you try to sandbox and restrict your AI agents running on your local machine, they might eventually be able to access any file in the file system.

Well, don't use secure enclave then, just file based private keys.

As an aside, that's probably one of the best formatted text diagrams I've seen. Did you use a specific tool for that, or via an LLM from a prompt?

I use 1Password's `op` for this, but with an allowance: my dev environment keys.

I found I was getting fingerprint fatigue. Do I need a fingerprint request every time my dev server wants to connect to dev Supabase? No. That's expected, and zero risk. There's no data there.

I worried that a nefarious request would be auto-approved by me. When you see 20 requests a day, your muscle memory just reaches for the sensor.

So I have a separate 1Password vault that a service account [0] can read. That token is in my environment as OP_SERVICE_ACCOUNT_TOKEN, which the `op` tool understands.

It also has access to a vault with 'AI-safe' keys that I want Claude to be able to access without asking me.

Now, these requests work invisibly. And when I see a fingerprint popup, it's unusual, and I don't auto-approve by habit.

I also keep an item called '_One-day keys' in a separate vault. (The underscore just pushing it to the top of the list for easy access.)

It has prod keys, mostly restricted read-only. If required, I move that over to the open vault. Claude knows this item and has instructions to remind me to move it back out when it's finished what it was doing.

[0]: https://www.1password.dev/service-accounts/get-started

1Password + `op` cli is a good alternative choice here.

+ fnox

Proton Pass with `pass-cli` has a similar thing, for anyone using that. You can give agents an expirable token and get an audit log of what item was read and when.

I believe 1Password has a sort of MCP server now as well, have you tried that out? I'm curious how well that works in place of using the CLI like this

I haven't, because I already had this configured.

MCP for this would feel like I was giving up control? I don't know exactly what that thing is doing. Whereas I know exactly how my configuration works.

bad = 1password == electron

I decided years ago that I want to protect my keys with a hardware device that is independent of the vendor of the machine that I'm currently using. I also want to have backup keys and I want to be able to freely move them around various physical locations. Or have a backup shipped to me across the world if necessary.

YubiKeys were the only solution that fit these requirements, so I went with those. I have been using them for the last ten years or so and I've been very happy with this solution. See https://github.com/drduh/YubiKey-Guide for a description of how to make your RSA keys stored on YubiKeys work with GPG and SSH at the same time.

The other option is to have device-bound keys and a script to sync them to all ssh servers you want to access.

Relying on a small set of ssh keys for a longer time is anyway not that great, it's best to have some mechanism to cycle them.

I wouldn't use any automated sync tool for that, just a script that ssh's into all the servers and replaces/edits authorized_keys if something changes.

I would never use something like this (https://github.com/shoenig/ssh-key-sync). It basically gives Github or someone who compromised Github access to all your systems.

The article starts on an incorrect premise.

The author says he doesn’t like the idea of having keys sitting on his file system ready to be snatched by bad actors.

That’s why they should be passphrase protected.

You use ssh agent to store the keys in memory and for convenience you can store the passphrases in keychain. MacOS OpenSSH has the UseKeychain config directive for that.

I use Yubikey/FIDO2 myself, but not because private keys cannot be protected on a file system.

was wondering the exact same thing. dude never heard of passphrases?

Secure Enclave is still more secure in that it should be impossible to access the private key. Password protected keys are still vulnerable to malware that can read the keyboard, trick you in to typing the password, or that have exploits in macOS to read the memory.

If you have malware that can read the keyboard, can't it just inject code via the keyboard to add their own authorized key to whatever server you're connecting to?

It is a different attack, though, that is not stealing your key.

Isn’t the macOS keychain user-readable by default?

Assuming the attacker has user rights (which it needs to read the key) it could also read the passphrase, right?

Update: I tried it out and stand corrected. ssh-add doesn’t store it in the user-readable keychain. So the passphrase is protected. (And also not recoverable by the user).

Do you type your passphrase every time you log into a remote machine? If not, the private key is in RAM and can be extracted by malware and stolen. If so, that's way more annoying than using touchid or some other physical proof of presence.

I used to install ssh_locker [1] (I don’t know if it still works), and have the passphrase in a keychain separate from the default `login` that I then set in Keychain Access to autolock after a set period of time. Handy for keeping the private key for a while in RAM and then autoremoved, instead of having it there for the whole session. It worked transparently and is a feature that should come with the OS.

[1]: https://github.com/ddribin/ssh_locker

ChatGPT says ssh_locker locked the keys with `ssh-add -x` which doesn’t necessarily remove them from RAM. Duh! It does point to suggested minimal changes to its source code to effectively accomplish that though.

Being able to extract a private key from ssh-agent's PR_SET_DUMPABLE=0 process would be a kernel bug; if you're sitting on such a vulnerability, please consider reporting it.

Key on disk plus a passphrase is still only 1FA. Key in the SE + an unseal PIN is 2FA. There's already plenty written about why one is better better than the other.

You should checkout the TKey (https://www.tillitis.se/products/tkey/)

It's effectively an open source version of a YubiKey, the hardware itself is all open source and it handles ed255519 SSH keys really well.

inb4 they're not the same, I know, I really like what the TKey team is doing.

I used yubikeys for ssh for years. First via the older clunky gpg as ssh key feature. Then via the FIDO api. My biggest issue was the chicken and egg issue when using this setup on a new machine or god forbid in a container etc. windows and WLS wasn’t super thrilled either. I switched to 1Password ssh because I actually like the fact that I can simply share my keys. It’s still not perfect. Agent forwarding needs an extra configuration and depending how many keys you have and how verbose your ssh config gets it becomes also very finicky. This solution feels for me like a slight setback because it’s a macOS only solution. If you have a Linux or windows machine next to a Mac you have to deal with the insecure key file on your hard drive again either via yubi keys or software solutions.

But I think I would take this over a yubikey. I really disliked the fact that one usb port was constantly in use.

you can’t just pop it out once you’re logged in?

Sure and pop in whenever I do a git commit? I also sign my commits. I used GPG (different key on the same hardware key) and now via SSH key. I had both a compact and bigger key. I got the compact key because my very first yubikey nearly broke. I lifted my Mac while it was connected and it cracked in the middle. I bought a compact one next which can stay inside and that one you don’t want to take out. It’s so small you’ll lose it. I know because that happened to my backup key … (that was actually the idea for the bigger one I bought but I lost the damn thing during the setup phase) But having the yubikey bound to your Mac at all times is also stupid because it doesn’t come with a fingerprint or other biometric sensor. The idea is that you use this thing as a token not that you leave the key in the lock at all times. For that alone I would favor the enclave solution.

The Yubikey 5 Nano and 5C Nano DO come with touch.

The idea is precisely that you keep them permanently connected in the laptop.

Touch is not the same as biometrics. I think they’re saying that leaving it plugged in means that anyone that can unlock your computer can also use/touch your yubikey.

The way I think of it is YubiKeys should be used to basically provision a computer with an approved device specific key. Whether it's a passkey or SE/TPM secured SSH/GPG/TLS key: the Yubikey holds the credential everyone trusts and therefore can be used from any device to gain access and enroll a new approved key.

Why do you share private keys?

SSH private keys should be passphrase protected.

You don’t have to do that if you use FIDO2 with a Yubikey.

Share as in storing my key in 1Password and use it from different machines. I generated the key from 1Password and don’t intend to export it.

You should reevaluate if you can instead use multiple public keys where you need to connect.

It’s a mind shift worth considering.

You then can accept that your ssh keys are different per hardware token (because the private key cannot be extracted).

No more sharing of private keys in your password manager.

I’m a bit lost and maybe something also got lost in translation. I use 1Password to store multiple ssh keys for different services. I have a very restrictive ssh config because I don’t like to use ssh agent which hands out all keys to different connections. I use one key for a set of machines for work. One for GitHub etc etc etc. I connect to these machines from different endpoints. And I don’t want to register each of these with a new custom keypair to all the services. Like GitHub. I have 1Password installed on all desktops I use so I pull them from there. I share the same dot files and configuration. For GitHub I actually need 3 keys. My private key, 2 for work that have special SSO permissions. I don’t want my private key to have access to the work repos that’s why I split and my company has 2 different enterprise accounts where I have 2 different user accounts.

You can use CA signed -sk keys to avoid the provisioning hassle. Provision the CA public key only onto hosts. Disclosure: Claude taught me this trick.

Secure Enclave, TPM and other such security features are unfortunately so badly documented and need so many hoops to jump through to get them working, with any mistake either causing you to be locked out completely or to not give you the protection you wanted. There really should be a better way to make these technologies usable...

These days I'm mainly doing development inside VM's. Previously I was embedding Github key to each VM, but since I setup Secure Enclave (with Secretive), I'm only forwarding it's agent to VM and each git action on origin now requires approval using fingerprint reader. I think this a good way to prevent malware from gaining access to github

Why not use PAT?

I’ve grown to appreciate ssh should only be used with git for signing commits and as a deploy key (eg in a CI system).

I always use https for day to day git operations. My keys reside in gopass and are extracted by gopass-git-credential when needed by git.

I use that within devcontainers

https://github.com/gopasspw/git-credential-gopass

Those access token can still be stolen just the same. The Secure Enclave is better because you can ask it to authorise the action, but you can never get the key out of it, so the latest malicious npm package can’t send off your access tokens or ssh keys.

absolute security does not exist, but each small improvement adds up. I quite like having to authorize each remote git action with Touch ID.

PAT are vulnerable, once stolen they can be used from anywhere until their (usually) long term expiry.

Better use short lived tokens with auto refresh. For example OAuth tokens. They can be used for the same use cases like PAT, but they expire after a max of 2 hours.

Which oauth tokens are you talking about? Because GitHub’s created by oauth or gh apps have a lifetime of either 8h or forever.

Gitlab uses 2h. TIL that GitHub uses 8h.

2 hours is plenty. The recent binance hack was 20 minutes after all. A 2 hour token is enough time to get all that can be gotten or done by a token in almost any system especially well defined ones like GH or GL.

It would be nice if GitHub or GitLab could limit a token to a given IP, but with how proxies and dynamic ips work I would imagine it would be a hassle to get it working correctly for everyone, but it’s better than nothing.

IP prefix should be enough to narrow down to your ISP + rough geographic location. Not perfect but requires no extra setup.

The `sc_auth` trick was posted about a year ago, since macOS 26 Tahoe added the SSH related functions into the keychain.dylib.

> https://news.ycombinator.com/item?id=46025721

One of the problems I constantly face is that the SSH configuration is not portable when I use these esoteric things. Even with Secretive (which plugs a simple SSH socket), remote agent forwarding sometimes fail. (ie. Due to the old version on the server or configuration issue, or something else setting SSH_AUTH_SOCK...)

Moreover, it is not possible to drop these files into a file-sharing folder, like OneDrive or iCloudDrive or SMB share, and share them with many hosts at the same time. (Especially when different operating systems are involved...)

I found the hacker way simplest and easiest; put a basic Makefile with bunch of rules, have a "central" host/machine to distribute the keys and configuration from that point on...

On macOS use “Secretive”. It’s a small app that can generate keys from Secure Enclave and prompts you with touchid whenever those keys are being used

On iOS/ipad/(also macOS) you can also use the SSH terminal emulator Termius which has support for SE keys built in as well. So I have the set of keys synced to my VPS, this way I know that only my physical devices can log in and nothing else.

I wish there was a way to cache the touch. As it stands, this is mostly unusable for commit signing in a rebase-heavy workflow.

In case you want to just have an encrypted SSH key with password in keychain, you can make it work automatically when logged in (and when Mac is unlocked) by putting in .ssh/config:

  Host github.com
    AddKeysToAgent yes
    UseKeychain yes
    IdentityFile ~/.ssh/id_ed25519

Docs: https://docs.github.com/en/authentication/connecting-to-gith...

Normally with gpg agent that leaves the key unlocked it is not a problem.

The thing I don't like about the Secure Enclave is that it does not yet support ed25519 keys.

Whats wrong with P256?

It supports it, but the constants are in the private Security.framework headers.

Author here. Thanks to js2 for posting this, and to everyone for the comments. I've learned a lot from this thread.

To answer the question a few people asked: I ended up using Secretive. The native approach works, but I couldn't live with the Touch ID prompt it shows. Secretive keeps the keys in the Secure Enclave too, with a much better prompt and per-key settings. I'm writing a part 2 about it, including forwarding the agent into a dev container so the key never enters the container.

What's the general consensus around ssh-agent?

It's often the case that we make much effort into securing the key but expose it via an open agent socket at a well known path or use an open control master path for multiplexing.

Certain automation and dev tools like Ansible make it a pain to work if agent key requires a confirmation.

Weirdly enough, this is _why_ I ended up using Secretive: I needed a second ssh-agent because selecting which keys are forwarded per-host is very fiddly, and while standard ssh-agent kinda supports it, 1Password doesn't. Anyway, _a_ solution for this is having separate SSH agents, and Secretive is another agent on top of 1Password.

I’ve used the 1Password SSH agent at work and had to disable it because of prompt fatigue.

Claude and Cursor love to do `git ls-remote` at random times, which makes 1Password show a prompt asking me for permission, even though they initiated it from a non-interactive shell.

So now they just fail silently at the password prompt over and over again.

I've started noticing this as well. I really like the 1Password ssh agent setup, but the agentic tooling background triggers is unnerving, and I don't want to setup a "default allow" as it would defeat the purpose.

Windows can do this too, btw: ssh-keygen -t ed25519-sk

It uses either the TPM with Windows Hello, or an external security key.

It might require downloading a newer Microsoft openssh release to generate the keys, but the current Windows 11 ssh can use those keys.

Some former context: https://news.ycombinator.com/item?id=46026043 briHass has been a very informative guy on this issue!

https://github.com/unreality/nCryptAgent works quite like Secretive

https://github.com/PowerShell/Win32-OpenSSH/issues/2040 https://github.com/PowerShell/Win32-OpenSSH/issues/2408 https://github.com/PowerShell/Win32-OpenSSH/issues/2413 so there are still some quirks at the moment

I guess the blog post is still relevant. But it's quite easy:

Download the newest release here: https://github.com/PowerShell/Win32-OpenSSH/releases. Just use ssh-keygen from the release to generate the key, the key itself works fine with the older ssh shipped with Windows.

Some hardware features must be present for it to work. But I guess all (or most) Windows 11 compatible devices will do fine.

From a user perspective, I've been happy with Secretive[0] for quite some time across several machines (mentioned in TFA).

[0]https://secretive.dev

Never missing an opportunity for self-promotion, if you use a lot of machines and have issues with agent forwarding and Git (i.e. because you're using a remote coding agent), I wrote https://github.com/anaisbetts/ts-ssh-agent - your keys are stored on a remote Tailscale node, and agent signing requests are verified via your Tailscale identity and gated by Tailscale access rules.

This means the machines you want have access to SSH (i.e. GitHub push/pull), but none of them have an actual SSH key - if a machine is compromised you drop it from Tailscale. More of a security/usability compromise than what OP is looking for, but solved a lot of frustrating paper cuts for me - I use it every day and I never think about SSH agents any more, it all just works

Great until Tailscale fails either completely or on that node. I did something similar but this was how it completely broke - once on a Raspberry Pi two metres away and once on a VPS two continents away.

Recoverable via console access but disruptive.

Still using Tailscale but have redesigned my setup and keep coding agents on a short leash. Also switched to internal Forgejo for speed and use GitHub as a push mirror.

I like a lot of the ideas in Tailscale, but I think I adopted too much of it in a fug of excitement and power.

Why would you trust the NIST P-256 curve?

It is not one of the cryptographically safe curves, likely intentionally so.

https://safecurves.cr.yp.to/

I appreciate DJB in trying to aim higher when it comes to security through his SafeCurves project, but ultimately NIST P-256 is good enough. Many of his criticisms are just nitpicks. Especially since Claude has since provided reverse engineered origin of the random seeds in NIST P-256.

Saying it is cryptographically unsafe is a wild exaggeration of what he says.

Apparently Claude "solved" the NIST curve mystery [1].

[1]: "Claude Solves the NIST Curve Seed Mystery: It Was Timestamps" - https://cellcog.ai/blog/claude-ecdsa-curve-seeds/

Not sure how many people feel like this, the risk in plain sight is a lot easier to handle than the risk hiding under the layers. You can keep shifting the storage for the key, one way or another you have to open up a channel to access to key or use the key. That channel would then become the vulnerability target.

To prove possession of a private key, one needs only to sign something with that key (this is how SSH key auth works). This is how things like the macOS Secure Enclave operate - the private key is stored in a separate hardware chip that only exposes an interface to sign something with that key, never to actually present the key. To obtain the key would require having physical access to the computer, ripping it open, and performing advanced deconstruction and analysis of that chip.

I dont want to be rude, I am aware of the operational semantics. Getting what you want to be signed with the key is the external channel operation I was referring to. In this particular case, somehow the attack vector being disabled is the actual private key being locked from any export. This gives a sense of security, however the channel abuse can bypass the security.

You’re right, but this is why the author doesn’t want to use the secure enclave without touchID, so that the channel being abused requires him being prompted and approving every abuse of the channel. This really is significantly more secure than the key just being on disk (obviously at the cost of convenience)

Its a rabbit hole, which is what I referred as layers of security/obscurity giving a sense of security. Theoretically the person touches the touchID for the key usage, however in reality the usage fatigue kicks in, performance considerations kick in and you end up with a small window where risk is considered worth the trade off. The key is in the cache available for the process/program that you already consented to in the last few occurrences without explicit prompt. The attack vector is that I am behaving nice for the first time to gain your trust, and then I do what I planned for. Worst, in supply chain attacks your program was compromised by a third party.

My original thought was that people often confuse complexity as security. Its added friction layer for sure, however it cuts both ways, makes slightly harder for every day hacker, the monitoring becomes harder as well.

I wish I could import an existing key. Also when sharing the pub key, as far as I understand, shares the hardware dependence, e.g. on GitHub.

Traditional TPM allow key import while Apple’s security enclave doesn’t. One has to trust the implemented RNG/seed/key generation.

I was looking in to this just earlier today. The native macos version worries me a little because it seems someone just happened to discover it in MacOS, rather than it being a documented feature. The worry being Apple could change or remove it later locking you out of your keys since they never advertised this as a thing you could do.

It is the same as you lost your device. You must have a second backup key, and treat one in Secure Enclave as disposable key.

Just to clarify this - you can have multiple public keys for the same user on the server end, in ~user/.ssh/authorized_keys. It's obvious when you know it, but I think it can be a source of confusion when discussing backup keys.

If someone like the native approach or is familiar with SeKey, I created sekey-sh to simplify the process: https://github.com/cavoirom/sekey-sh

Work on macOS 26 and later.

It's a shame that the poster doesn't mention what they ended up using instead in their update. Presumably a hardware key.

Has anyone managed to extract a fingerprint reader from an Apple Magic Keyboard? I usually run my Macs in clamshell mode.

I have seen a few of these done at this point (i.e. hardware extracted from a Magic Keyboard)

This is the most recent one I found via Googling, I have not actually used this product:

https://standalone-touch-id.square.site/

> That ssh: at the end is the FIDO2 application ID — it’s part of the key, not a comment.

I think this is incorrect and the "ssh:" at the end is indeed a comment.

You're right, thanks. The trailing ssh: is the comment: changing or removing it leaves the fingerprint the same. The FIDO application ID is also encoded inside the key blob, and it's also "ssh:", which is what confused me. I'll fix the post.

Somebody posted a tool here in the last couple of weeks that was doing this (using macos secure storage for local credentials/ keys)

Any reason to not store in a kdbx file this way your keys are platform independent.

Isn't a GitHub app project Secretive doing that but better?

No app is better.

I've been using Secretive (a nice software wrapper for these) for a few days for my Github keys (where 1Password holds the rest of my SSH keys). It works nicely, but obviously you can't back up a key that started life in a secure enclave, so you'll need alternative access arrangements for anything you setup that way.

2nd this. Found out about it when this type of thing came up about a week ago. I had a hard time getting the stock stuff going but Secretive made it easy to set up and I love using it.

Definitely a recco from me as well. -- git hub here: https://github.com/maxgoedjen/secretive

The details of using the SE are interesting. I still don't understand the threat analysis here. Basically here's the lede:

> Any malicious script that gets access to my filesystem could just copy them and get into all my servers.

So this is postulating a "malicious script" that has access to your filesystem but not the running system. Because if it's running on the actual system it doesn't need the key, it can just execute your remote stuff on its own. Or it can get the key by MitMing you by making your next "ssh" invocation steal your passphrase, or just read the unencrypted key out of the ssh process, or even just reimplement ssh to do the SE negotiation on its own. Or...

Like, there's near zero added security here. The only scenario I can think of that would have any meaning is someone getting access to an offline image of your filesystem, an attack already prevented by drive encryption (and, perhaps, already defeated by insecure backups!).

You see occasional attempts to use TPMs for similar purposes, and they're similarly silly. People need to understand that the TPM/SE exists for the benefit of third party authentication. It's not for you, the operator. It's there so that your bank/employer/intelligence-agency/whatever can know that the human being doing authentication is using the same device they've been known to use before.

> it can just execute your remote stuff on its own

Presumably biometrics are required to use the key, so they have to convince you to prove presence when you aren’t expecting it?

> Or it can get the key by MitMing you by making your next "ssh" invocation steal your passphrase

What passphrase?

> or just read the unencrypted key out of the ssh process

The key never leaves the SE, so this is not possible.

> or even just reimplement ssh to do the SE negotiation on its own

See first point and biometrics.

I have applied this at our company using Secretive, and extended to sudo over SSH: The remote end uses an SSH Agent PAM module that forwards sudo requests to the connected SSH Agent, which is Secretive running on the employee Macs, so we get remote sudo with TouchID prompts.

No more passwords to enter anywhere, and whatever an (AI) agent or malware is trying to do will require a human interaction at least, and not work when the screen is locked. The public keys authorized for this are distributed to the fleet via puppet, so we get control over who gets to sudo permissions and can easily provision or decommission machines.

Pretty stoked about it so far.

it’s a worthy experiment but I wouldn’t want hobbyists making life miserable for the rest of us.

There’s no reason the private key needs to be stored in Secure Enclave. Your passkeys are in the MacOS Keychain, encrypted using the Secure Enclave. They are decrypted when iCloud transfers them to a new machine.

A similar protocol could be used with ssh keys. Keep the keys on disk as usual, making them easy to back up. Encrypt them using the enclave. You can use the Secure Enclave to decrypt the key for backing up (with a backup-specific secret).

This way all of the protocols and tooling remains the same, except for obtaining the SSH key encryption secret from Secure Enclave. Backup, ssh login, ssh agent all use the same keys.

Do what Apple does. Making the process more difficult actually makes security worse.

SSH keys at ~/.ssh it's a disaster. These should have been handled by something like factotum in 9front, but for Unix/POSIX.

We should have had this 20 years ago. It is almost pathological how difficult it is to reliably use hardware keys as ssh credentials.

ed25519-sk werks on my machine...

Unless you specifically mean (f)TPMs/secure envlaves.

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