• Getting started
    • ➟ Accessing your virtual machine 
$ ssh-keygen  -a 256 -t ed25519 ❶ -C "$(hostname)-$(date +'%d-%m-%Y')"
Generating public/private ed25519 key pair.
Enter file in which to save the key (/home/foo/.ssh/id_ed25519): 
Created directory '/home/foo/.ssh'.
Enter passphrase (empty for no passphrase): ❷
Enter same passphrase again: 
Your identification has been saved in /home/foo/.ssh/id_ed25519 ❸
Your public key has been saved in /home/foo/.ssh/id_ed25519.pub ❹
...
~/.ssh$ cd ~/.ssh
/home/foo/.ssh cp id_ed25519.pub authorized_keys
mistudent@w10m:~/.ssh$ ls -al
total 24
drwxrwx---+  2 student mi    0 Okt 17 17:45 .
drwx------+ 32 student mi    0 Okt 17 17:44 ..
-rwxrwx---+  1 student mi  396 Okt 17 17:45 authorized_keys ❶
-rwxrwx---+  1 student mi 1675 Okt 17 17:38 id_ed25519 ❷
-rwxrwx---+  1 student mi  396 Okt 17 17:38 id_ed25519.pub ❸

❶

Allowed keys to log on to current machine.

❷

Private key

❸

Corresponding public key

 
mistudent@w10m:~/.ssh$ getfacl  authorized_keys
# file: authorized_keys
# owner: mistudent
# group: mi
user::rwx
user:mistudent:rwx
group::---
group:users:---
mask::rwx
other::---
foo@w10m:~/.ssh$ setfacl -m user:foo:--- authorized_keys
foo@w10m:~/.ssh$ setfacl -m user::rw- authorized_keys
foo@w10m:~/.ssh$ getfacl authorized_keys
   ...
user::rw-
user:foo:---
group::---
group:users:---
mask::---
other::---

foo@w10m:~/ssh$ ls -al authorized_keys
-rw-------+ 1 foo mi 396 Okt 17 17:45 authorized_keys
foo@w10m:~/.ssh$ ls -al
total 32
drwx------+  2 mistudent mi    0 Okt 17 17:44 .
drwx------+ 32 mistudent mi    0 Okt 17 17:44 ..
-rw-------+  1 mistudent mi 1132 Okt 17 17:40 authorized_keys
-rw-------+  1 mistudent mi 1679 Okt 11 14:46 id_ed25519
-rw-r--r--+  1 mistudent mi  396 Okt 11 14:46 id_ed25519.pub
-rw-------+  1 mistudent mi  442 Okt 11 14:49 known_hosts
ssh  root@sdi14a.mi.hdm-stuttgart.de
The authenticity of host 'sdi14a.mi.hdm-stuttgart.de (141.62.75.114)' can't be established.
ED25519 key fingerprint is SHA256:sEagSHefcv9OkiFibKIZFlPL/4FxbO+9kvJnwkV7ltU.
This key is not known by any other names
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added 'sdi14a.mi.hdm-stuttgart.de' (ED25519) to the list of known hosts.