I went ahead with this prompt-



 ghosh-r:


Enter passphrase (empty for no passphrase):



Let’s say I typed in “foobarbaz”.
It is successful, and it shows-

Your identification has been saved in /home/<user>/.ssh/google_compute_engine
Your public key has been saved in /home/<user>/.ssh/google_compute_engine.pub
The key fingerprint is:
SHA256: <sha256 code> <user>@<computer-name>
The key’s randomart image is:
±–[RSA 3072]----+
|                     |
|                     |
|                     |
|                     |
|                     |
|                     |
|                     |
|                     |
|                     |
±—[SHA256]-----+

(I removed the characters)
This time, and whenever I run
$ gcloud alpha compute tpus tpu-vm ssh <name> --zone us-central1-a --project hf-flax

I get-

SSH: Attempting to connect to worker 0…
sign_and_send_pubkey: signing failed for RSA “/home/<user>/.ssh/google_compute_engine” from agent: agent refused operation
<user>@x.x.x.x: Permission denied (publickey).
Retrying: SSH command error: [/usr/bin/ssh] exited with return code [255].
SSH: Attempting to connect to worker 0…
sign_and_send_pubkey: signing failed for RSA “/home/<user>/.ssh/google_compute_engine” from agent: agent refused operation
<user>@x.x.x.x: Permission denied (publickey).
Retrying: SSH command error: [/usr/bin/ssh] exited with return code [255].
^C
Command killed by keyboard interrupt

Then I get asked to enter my password repeatedly. I type in the password, it gets accepted, then another prompt appears.
It says- “Enter password to unlock the private key, an application wants to access the private key “<user>@<computer>”, but it is locked.”

$ cat /etc/apt/sources.list.d/google-cloud-sdk.list

returns-

deb [signed-by=/usr/share/keyrings/cloud.google.gpg] https://packages.cloud.google.com/apt cloud-sdk main