ssh-keygen命令来自英文词组“SSH key generate”的缩写，其功能是用于生成SSH密钥文件。ssh-keygen命令能够对SSH密钥文件进行生成、管理、转换等工作，支持RSA和DSA两种密钥格式。

语法格式：ssh-keygen [参数] [对象]

常用参数：

-b设置密钥长度
-B显示密钥文件摘要
-c设置注释信息
-e读取已有密钥文件
-f设置保存密钥的文件名
-F设置搜索的主机名
-i读取SSH2兼容格式的未加密文件
-I显示指定公钥文件的指纹信息
-N设置新密码
-p设置私钥文件的密码
-P提供旧密码
-q静默执行模式
-r显示指定公钥文件
-t设置要创建的密钥类型
-v显示执行过程详细信息

参考示例

创建一个SSH密钥文件：

[root@linux-arae-cc ~]# ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): 直接回车，以默认路径保存
Created directory '/root/.ssh'.
Enter passphrase (empty for no passphrase): 直接回车，不额外设置密钥密码
Enter same passphrase again: 直接回车，确认不额外设置密钥密码
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:tUB6SjLnvqM7p2l+bmHUZGNqUyyOPmXGyiMp3tC9xNA root@linux-arae-cc.com
The key's randomart image is:
+---[RSA 2048]----+
|       ..        |
|      .oB        |
|    +++Oo..      |
|   ..E@o.o .     |
|  .++Bo.S .      |
|..o.*=o          |
|..o..+o.         |
| . .oo=.         |
|   o*Xo.         |
+----[SHA256]-----+

手动指定加密格式并添加注释信息，创建一个SSH密钥文件

[root@linux-arae-cc ~]# ssh-keygen -t rsa -C "welcome to linux.arae.cc"
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): 直接回车，以默认路径保存
Created directory '/root/.ssh'.
Enter passphrase (empty for no passphrase): 直接回车，不额外设置密钥密码
Enter same passphrase again: 直接回车，确认不额外设置密钥密码
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:OQodor0B83DoxbFOY+KUo0swrQAgo8tL3qIHA0t40gQ welcome to linux.arae.cc
The key's randomart image is:
+---[RSA 2048]----+
|E.  .            |
|+o.+ o           |
|*o@ X .          |
|BXo/ + . .       |
|*B+ * . S        |
|B.o  + . .       |
|.* .. .          |
|. o              |
|..               |
+----[SHA256]-----+