How can I get such a key into my iPhone too, so that I can sign emails and file and such with the same private key when I'm on my phone, and my public key is valid for all such operations ? Will iCloud take care of that ? And then I want it all usable from my (multiple) email clients...
Native Secure Enclave backed SSH keys on macOS
61–70 of 204 posts
Re: Native Secure Enclave backed SSH keys on macOS
#62Earlier quoted context omitted.
Inability to export the private key is no different from using an YubiKey? You can't "backup" the private key they generate either.
Yeah, that is why you should not [always (depends on your use case)] generate it on a YubiKey. You need to have: - an offline master private key backup (air-gapped) - primary YubiKey (daily use) - backup YubiKey (locked away) - revocation certificate (separate storage) (it is your kill-switch) Having a second YubiKey enrolled is the standard practice. What people do wrong is: - They generate directly on YubiKey - The…
> Yeah, that is why you should not generate it on a YubiKey
No. You should ALWAYS generate on the Yubikey. That's the whole point.
Your backup is one (or more) other keys.
Re: Native Secure Enclave backed SSH keys on macOS
#63Earlier quoted context omitted.
Inability to export the private key is no different from using an YubiKey? You can't "backup" the private key they generate either.
Which makes yubikey impossible to use with geographically distributed backups. You need the backup available at all times for when you want to register with any new service. This is why you should use a device which allows exporting the seed, like e.g. multi purpose hardware crypto wallets.
> Which makes yubikey impossible to use with geographically distributed backups.
Huh ?
You do know you can wrap a symmetric key with multiple asymmetric keys, right ?
Re: Native Secure Enclave backed SSH keys on macOS
#64Earlier quoted context omitted.
I've been in the security space for 25 years, and understand the theory of PKI. But I've also been in the ops space for 30 years, and understand that if you don't balance security theory with operational practice, critical business functions can fail. Ideally yes, the private key is never seen. In reality, it needs to be backed up in a secure place so it can be restored in the event of a failure.
You can use more than one key you know. Keep the private key you actively use in the secure enclave. The system you actively use is most at risk. Keep a secondary offline private key as backup. You can generate and store it in a secure location, and never move it around. Airgapped even if you want. You could even use a yubikey or other hardware for the secondary key giving you two hard to export keys. Distribute pub…
Yeah but if you get a new device, you have to go add its pubkey to every server you ever use. I wish there were an easier way, otherwise it's understandable that people copy privkeys.
Re: Native Secure Enclave backed SSH keys on macOS
#65How can I get such a key into my iPhone too, so that I can sign emails and file and such with the same private key when I'm on my phone, and my public key is valid for all such operations ? Will iCloud take care of that ? And then I want it all usable from my (multiple) email clients...
These aren't synced over iCloud
What you're thinking of are Passkeys. Which are synced. Somebody would have to write an SecurityKeyProvider that talks to the Passkey API instead.
Actually I don't think it's completely impossible. The only thing is that passkeys are origin-bound. They belong to a specific AppBundle ID or domain name. If say Secretive would add passkey support then that specific public/private keypair can't be used by another app. Though it does sync across instances of the app across devices.
Re: Native Secure Enclave backed SSH keys on macOS
#66Earlier quoted context omitted.
>The key is stored encrypted with a unique symmetric key that only your secure enclave knows until the point that you export it. It then re-encrypts it with the password. But what's the security benefit of this compared to having a keyfile? So far as I can tell from the commands you provided, there's no real difference, aside from a hacker having to modify their stealer script slightly.
Why is it more secure: a key file on disk is decrypted into memory every time you enter your passphrase. It means the key is around in plain text in the memory of ssh or ssh-agent. Which means it's extractable by an attacker. An exportable key does all the signing inside the secure enclave and never exposes the decrypted key to OS memory. The exported key you can keep in a safe for disaster recovery. You shouldn't ke…
> The exported key you can keep in a safe for disaster recovery.
No. Your "disaster recovery" should be either a second device with a Secure Enclave, or a Yubikey.
Making it exportable from the Secure Enclave defeats the whole purpose.
Re: Native Secure Enclave backed SSH keys on macOS
#67Earlier quoted context omitted.
>The key is stored encrypted with a unique symmetric key that only your secure enclave knows until the point that you export it. It then re-encrypts it with the password. But what's the security benefit of this compared to having a keyfile? So far as I can tell from the commands you provided, there's no real difference, aside from a hacker having to modify their stealer script slightly.
Why is it more secure: a key file on disk is decrypted into memory every time you enter your passphrase. It means the key is around in plain text in the memory of ssh or ssh-agent. Which means it's extractable by an attacker. An exportable key does all the signing inside the secure enclave and never exposes the decrypted key to OS memory. The exported key you can keep in a safe for disaster recovery. You shouldn't ke…
>It means the key is around in plain text in the memory of ssh or ssh-agent. Which means it's extractable by an attacker. An exportable key does all the signing inside the secure enclave and never exposes the decrypted key to OS memory.
But malware can just tell the secure enclave to export the key? Yes, they'll have to write new code to do that, but it's not particularly hard (it's 1 line code from your example above), and it's security through obscurity.
Re: Native Secure Enclave backed SSH keys on macOS
#68Secretive is a bit friendlier to set up but I'll probably switch to this anyway so I have one less app on my computer. Plugging my blog post for how to achieve this on Windows 11: https://cedwards.xyz/tpm-backed-ssh-keys-on-windows-11/
Is storing ssh-key in tpm possible on Linux?
https://github.com/Foxboron/ssh-tpm-agent works well for me
Re: Native Secure Enclave backed SSH keys on macOS
#69This exists: https://github.com/facebookincubator/sks . It's a golang library that abstracts usage of ssh keys backed by hardware on all sorts of devices - mostly designed for laptops, but supports Linux, Windows and MacOs
A golang library is cool, but it doesn't give you a working ssh-agent. I started working on one few years ago: https://github.com/Foxboron/ssh-tpm-agent
I've been using this for a ~year now and it works very well. Thanks!
Re: Native Secure Enclave backed SSH keys on macOS
#70Earlier quoted context omitted.
Why is it more secure: a key file on disk is decrypted into memory every time you enter your passphrase. It means the key is around in plain text in the memory of ssh or ssh-agent. Which means it's extractable by an attacker. An exportable key does all the signing inside the secure enclave and never exposes the decrypted key to OS memory. The exported key you can keep in a safe for disaster recovery. You shouldn't ke…
>It means the key is around in plain text in the memory of ssh or ssh-agent. Which means it's extractable by an attacker. An exportable key does all the signing inside the secure enclave and never exposes the decrypted key to OS memory. But malware can just tell the secure enclave to export the key? Yes, they'll have to write new code to do that, but it's not particularly hard (it's 1 line code from your example abov…
The malware would have to prompt for biometric authentication before exporting.