centos7 设置ssh_key 登陆公钥与密钥，借助工具生成 .ppk 文件，

这里选择不对root进行直接操作，也就是会出现各个用户所对应的key

1.新增登陆用户,分配root权限组

[root@localhost ~]# adduser zhw2
[root@localhost ~]# passwd zhw2
Changing password for user zhw2.
New password:
BAD PASSWORD: The password is shorter than 8 characters
Retype new password:
passwd: all authentication tokens updated successfully.

分配权限组

[root@localhost ~]# visudo

root    ALL=(ALL)       ALLzhw     ALL=(ALL)       ALL    #添加
zhw2    ALL=(ALL)       ALL    #添加

2.修改ssh服务器配置文件

[root@localhost ~]# vim /etc/ssh/sshd_config

修改对应位置

#允许root认证登录
PermitRootLogin yes#允许密钥认证
#RSAAuthentication （rsa认证）是只支持第1代ssh通讯协议使用的配置项，在CentOS7.4中被废除了，而且前面提到过CentOS7开始预设使用第二代通讯协议，在CentOS7.4中没有找到指定协议版本的配置行，
RSAAuthentication yes  #第2代ssh通讯协议的密钥验证选项是
PubkeyAuthentication yes#默认公钥存放的位置
AuthorizedKeysFile  .ssh/authorized_keysPasswordAuthentication yes  #可使用密码进行ssh登录

3.重启ssh服务器

service sshd restart

4.切换用户到zhw2

[zhw2@localhost ~]$ ssh-keygen -t rsa
回车到结束！

id_rsa.pub(公钥)

id_rsa(私钥)

[zhw2@localhost ~]$ ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/zhw2/.ssh/id_rsa):
Created directory '/home/zhw2/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/zhw2/.ssh/id_rsa.
Your public key has been saved in /home/zhw2/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:ejpL30daxTyQHAKqBZQ5omG+9krbXovtt75ZAR6Wikg zhw2@localhost.localdomain
The key's randomart image is:
+---[RSA 2048]----+
|   .oo  .....o   |
|... +. ..  .+    |
|oE . .o=     +   |
|o.. .o+ o     =  |
| ..... .S.   . . |
| o     .  . o    |
|...  .o .. +     |
|. o.+.o=o.. .    |
| oo+.+=B+ ..     |
+----[SHA256]-----+

切换到用户目录，将公钥文件重命名为authorized_keys

[zhw2@localhost ~]$ cd /home/zhw2/.ssh/[zhw2@localhost .ssh]$ mv id_rsa.pub authorized_keys

将目录.ssh权限设置为700，公钥文件authorized_keys设置为644

[zhw2@localhost .ssh]$ chmod 700 ../.ssh/
[zhw2@localhost .ssh]$ chmod 644 authorized_keys

5.进行ssh测试（针对生成key的用户组）

[zhw2@localhost ~]$ ssh 192.168.163.122
The authenticity of host '192.168.163.122 (192.168.163.122)' can't be established.
ECDSA key fingerprint is SHA256:jROccStnTU3ONKCFDDWC7hDJe/uFppaZ45LImsl8SNQ.
ECDSA key fingerprint is MD5:f9:09:ad:29:66:06:1d:13:ab:7f:71:f9:25:6e:99:e0.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.163.122' (ECDSA) to the list of known hosts.
Last login: Tue Mar 12 02:20:39 2019
[zhw2@localhost ~]$

6.下载私钥，putty远程登陆。切换到root。下载私钥文件到本地（也可用winscp 直接下载）

使用puttygen.exe，生成ppk文件