Choose the Ed25519 host-key pair used by an OpenSSH server to prove its server identity.
Do not choose a personal user login key.
Which pair is appropriate?
/etc/ssh/ssh_host_*_key and its .pub file are server host-identity keys. Client users verify the identity through known_hosts.
Detailed explanation
/etc/ssh/ssh_host_ed25519_key と /etc/ssh/ssh_host_ed25519_key.pubCorrect. It is the server's Ed25519 host-key pair.
Correct. It is the server's Ed25519 host-key pair.
~/.ssh/id_ed25519 と ~/.ssh/id_ed25519.pubIncorrect. These are normally a client user's identity keys.
Incorrect. These are normally a client user's identity keys.
~/.ssh/authorized_keys と ~/.ssh/known_hostsIncorrect. These are databases for authorized client keys and known server keys, not a pair.
Incorrect. These are databases for authorized client keys and known server keys, not a pair.
/etc/ssh/sshd_config と /etc/ssh/ssh_configIncorrect. They are configuration files, not cryptographic keys.
Incorrect. They are configuration files, not cryptographic keys.
Try it yourself
An example you can run in a temporary verification environment.
printf '%s
' '/etc/ssh/ssh_host_ed25519_key=server private host key' '.pub=server public host key'Expected result
/etc/ssh/ssh_host_ed25519_key=server private host key
.pub=server public host keyKey points
- Host identity
- Keep the private key on the server
- Distinguish user identity keys
Notes
- Environment: OpenSSH key file役割対応表
- Command output formatting can vary slightly by distribution or tool version.
- Run the example in a temporary directory or process when possible.
Foundation review
Read the scope first
Check whether the command acts on the current shell, a new process, an existing process, or a file.
Verify the observable result
Use the supplied command and compare the output with the expected result.