ssh-keygen ##生成密钥的命令
Enter file in which to save the key(/root/.ssh/id_rsa): ##指定保存加密字符的文件(使用默认)
Enter passphrase(empty for no passphrase): ##设定密码(使用空密码)
Enter same passphrase again: ##确认密码
Your identification has been saved in /root/.ssh/id_rsa. ##私钥(钥匙)
Your public key has been saved in /root/.ssh/id_rsa.pub. ##公钥(锁)