公開鍵を使ってsshに接続

接続元で、公開鍵と鍵ペアと作ります。

$ ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/hoge/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/hoge/.ssh/id_rsa.
Your public key has been saved in /home/hoge/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:6QIg7y3cG5JtHPILGkSKE480kwmY5EbljMiUXwQ2yAKB48 hoge@hogehoge The key's randomart image is:
+---[RSA 2048]----+
|*%=+o            |
|BE*oo            |
|*+* B.B          |
|o= +. .  .       |
| oo.oo  S        |
|oo.Ooo .         |
|o B.O . .        |
| o = + .         |
|.   o            |
+----[SHA256]-----+
$ 
$ ls .ssh/id*
.ssh/id_rsa  .ssh/id_rsa.pub

$ ssh-keygen -t rsa

Generating public/private rsa key pair.

Enter file in which to save the key (/home/hoge/.ssh/id_rsa):

Enter passphrase (empty for no passphrase):

Enter same passphrase again:

Your identification has been saved in /home/hoge/.ssh/id_rsa.

Your public key has been saved in /home/hoge/.ssh/id_rsa.pub.

The key fingerprint is:

SHA256:6QIg7y3cG5JtHPILGkSKE480kwmY5EbljMiUXwQ2yAKB48 hoge@hogehoge The key's randomart image is:

+---[RSA 2048]----+

|*%=+o |

|BE*oo |

|*+* B.B |

|o= +. . . |

| oo.oo S |

|oo.Ooo . |

|o B.O . . |

| o = + . |

|. o |

+----[SHA256]-----+

$ ls .ssh/id*

.ssh/id_rsa .ssh/id_rsa.pub

作った鍵の公開鍵(id_rsa.pub)だけを、接続先のサーバの “~/.ssh/authorized_keys” に追加します。（ない場合は作られます。）

# 接続元
$ scp .ssh/id_rsa.pub example.com:~/
hoge@example.com's password: 
id_rsa.pub                                                                                 100%  402   353.3KB/s   00:00  

# 接続先
$ cat id_rsa.pub >> .ssh/authorized_keys

# 接続元

$ scp .ssh/id_rsa.pub example.com:~/

hoge@example.com's password:

id_rsa.pub 100% 402 353.3KB/s 00:00

# 接続先

$ cat id_rsa.pub >> .ssh/authorized_keys

これで完了。
公開鍵認証でssh接続できるか確認してみてください。