SSH connections to macOS Ventura with ssh key

[Jbrev3]

I am able to SSH from my iPad to my Mac with a username and password, but I haven't been able to figure out how to SSH using key authentication.

I successfully generate the keys using ssh-keygen in the terminal in the code app on my iPad, but how to I get to key to the ~/.ssh/authorized_keys file on my Mac? ssh-copy-id does not seem to work. I did copy the .pub key, sign on to my Mac with a password, and then paste the key in the authorized_keys file. However, when I try to sign on, I get "Authorization failed" in the app. This is perhaps similar to issue #688.

Note: I am able to ssh to my Mac using another key on another device, so I think the Mac side is set up correctly.

I have very little experience with SSH, and this is my first post, so let me know if you need additional information.

[bummoblizard]

Hi. I am able to reproduce this problem. Seems like the last update broke ssh using private keys. I will into this and issue a fix.

[bummoblizard]

@Jbrev3 Which macOS version are you on?

[bummoblizard]

This is actually a compatibility issue with macOS Ventura. The new OS requires a more secure hash algorithm for public keys. I'll need to update ssh-keygen for this.

As a workaround:

• add the following entries in /private/etc/ssh/sshd_config on your Mac

HostkeyAlgorithms +ssh-rsa
PubkeyAcceptedAlgorithms +ssh-rsa

• Run sudo launchctl stop com.openssh.sshd (This restarts the ssh service)

[bummoblizard]

Unfortunately this requires a reimplementation of ssh connection and will take some time but I will prioritise on fixing this.

[Jbrev3]

I have Ventura 13.1. And I verified your solution worked. Thank you!

[bummoblizard]

Update: It is also possible generate a supported key-pair by running ssh-keygen -t ed25519 so that macOS will accept the connection. In the latest TestFlight version, you might manually specify a custom private key to take advantage of this.