使用SecureCRT生成公钥免密SSH登陆CentOS8_crt许可证

1.使用SecureCRT生成公钥和私钥

​ 选择Tools>>Create Public Key…，生成公钥和私钥

​ 密钥类型选择RSA

​ 加密私钥，加密密码为888888（可选择不加密）

​ RSA密钥长度设置为2048位

​ 选择第2个OpenSSH密钥格式，保存公钥和私钥到本地磁盘目录

2.上传SecureCRT生成的公钥到CentOS

​ 进入/root/.ssh目录，修改authorized_keys权限为400

[root@vps ~]# cd /root/.ssh/
[root@vps ~]# chmod 400 authorized_keys
[root@vps .ssh]# ll
total 16
-r--------. 1 root root  964 Jan 10 04:14 authorized_keys
[root@vps .ssh]# 
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​ 安装lrzsz用于SecureCRT上传文件（也可用WinSCP上传）

[root@vps .ssh]# dnf install lrzsz
Last metadata expiration check: 0:19:33 ago on Mon 10 Jan 2022 04:37:48 AM PST.
Dependencies resolved.
===========================================================================================================================================
 Package                       Architecture                   Version                                 Repository                      Size
===========================================================================================================================================
Installing:
 lrzsz                         x86_64                         0.12.20-43.el8                          BaseOS                          84 k

Transaction Summary
===========================================================================================================================================
Install  1 Package

Total download size: 84 k
Installed size: 190 k
Is this ok [y/N]: y
Downloading Packages:
lrzsz-0.12.20-43.el8.x86_64.rpm                                                                            1.0 MB/s |  84 kB     00:00    
-------------------------------------------------------------------------------------------------------------------------------------------
Total                                                                                                      383 kB/s |  84 kB     00:00     
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                                                                                   1/1 
  Installing       : lrzsz-0.12.20-43.el8.x86_64                                                                                       1/1 
  Running scriptlet: lrzsz-0.12.20-43.el8.x86_64                                                                                       1/1 
  Verifying        : lrzsz-0.12.20-43.el8.x86_64                                                                                       1/1 

Installed:
  lrzsz-0.12.20-43.el8.x86_64                                                                                                              

Complete!
[root@vps .ssh]# 
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​ 选择Transfer>>Zmodem Upload List…添加需要上传的公钥后进行上传

​ 上传成功如下显示

[root@vps .ssh]# rz
rz waiting to receive.
Starting zmodem transfer.  Press Ctrl+C to cancel.
Transferring Identity.pub...
  100%     395 bytes  395 bytes/sec 00:00:01       0 Errors  

[root@vps .ssh]# ll
total 20
-r--------. 1 root root  964 Jan 10 04:14 authorized_keys
-rw-r--r--. 1 root root  395 Jan 10 04:54 Identity.pub
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3.添加公钥到授权文件

​ CentOS服务器生成RSA密钥对

[root@vps .ssh]# ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 888888 #加密密钥，留空为不加密#
Enter same passphrase again: 888888
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:OZcIIaYmj5rudACS94/RZ6e3ejtN3fUw6LkX+EzKf0k root@vps
The key's randomart image is:
+---[RSA 3072]----+
|    o .          |
| . o . .         |
|= +   .      .   |
|o* . . . o .. o .|
|... o . S +. + +o|
|...  + o =  = +Eo|
|o. .. . . .+ *...|
|o .      .o.= +..|
|.o      .ooo o.. |
+----[SHA256]-----+
[root@vps .ssh]# ll
total 20
-r--------. 1 root root  402 Jan 10 04:10 authorized_keys
-rw-r--r--. 1 root root  402 Jan 10 02:11 Identity.pub
-rw-------. 1 root root 2635 Jan 10 04:14 id_rsa
-rw-r--r--. 1 root root  562 Jan 10 04:14 id_rsa.pub
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​ 添加服务器公钥和本地客户端公钥到授权文件

[root@vps .ssh]# cat id_rsa.pub >>authorized_keys
[root@vps .ssh]# cat Identity.pub >>authorized_keys
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4.修改SSH配置文件，允许使用公钥免密登录

​ 修改SSH配置文件，启用公钥认证

[root@vps .ssh]# vim /etc/ssh/sshd_config
#启用公钥认证
PubkeyAuthentication yes
#公钥认证授权文件位置
AuthorizedKeysFile      .ssh/authorized_keys 
#禁用密码登录方式（也可选择yes，保留原密码认证方式）
PasswordAuthentication no 
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​ 重启sshd服务

[root@vps .ssh]# systemctl restart sshd
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5.使用公钥登录CentOS系统

​ SSH属性取消勾选密码登录

​ 输入SecureCRT创建密钥对时私钥的加密密码888888

​ 登录成功

Activate the web console with: systemctl enable --now cockpit.socket

Last login: Mon Jan 10 04:16:20 2022 from 120.130.12.18
[root@vps ~]# 
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