本文讲解如何用openssh生成ed25519的密钥对并实现服务器间免密钥登录。

注意：所有操作均在客户机侧

一、生成 ED25519 密钥

用需要免密登录的用户（本例为username） 运行“ssh-keygen -t ed25519 -b 256”

<code>[username@localhost ~]$ ssh-keygen -t ed25519 -b 256

Generating public/private ed25519 key pair.

Enter file in which to save the key (/home/username/.ssh/id_ed25519):

Enter passphrase (empty for no passphrase):

Enter same passphrase again:

Your identification has been saved in /home/username/.ssh/id_ed25519

Your public key has been saved in /home/username/.ssh/id_ed25519.pub

The key fingerprint is:

SHA256:TxLFDN0ERV3qM7d0OfTXCylXHrXQilvZTymabIcYhTE username@localhost.localdomain

The key's randomart image is:

+--[ED25519 256]--+

| .E=*+o..o|

| o=.. ooo|

| . . . ==.|

| o . *=o*|

| S =.*+=*B|

| = Bo.o+B|

| o . o |

| |

| |

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

[username@localhost ~]$

一路回车，即可看到在当前用户家目录下生成了.ssh/id_ed25519的私钥和.ssh/id_ed25519.pub公钥文件

二、将公钥文件传给远端服务器对应帐号

使用 ssh-copy-id 命令来完成

[username@localhost ~]$ ssh-copy-id -i ~/.ssh/id_ed25519 -p4422 username@192.168.1.76

/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/home/username/.ssh/id_ed25519.pub"

/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed

/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys

(username@192.168.1.76) Password:

Number of key(s) added: 1

Now try logging into the machine, with: "ssh -p 4422 'username@192.168.1.76'"

and check to make sure that only the key(s) you wanted were added.

[username@localhost ~]$

三、测试验证

[username@localhost ~]$ ssh -p4422 username@192.168.1.75

Last login: Tue May 28 17:22:38 2024

Authorized users only. All activities may be monitored and reported.

[username@localhost ~]$

可以看到，现在已经不需要密码即可以登录了。