假设本地主机linux100,远程主机linux200
一，在linux100主机里的用户
运行
#ssh-keygen -t rsa
结果如下
QUOTE:
Generating public/private rsa key pair.
Enter file in which to save the key (/home/.username/ssh/id_rsa):#回车
Enter passphrase (empty for no passphrase):#回车
Enter same passphrase again:#回车
Your identification has been saved in /home/.username /.ssh/id_rsa.
Your public key has been saved in /home/.username /.ssh/id_rsa.pub.
The key fingerprint is:
38:25:c1:4d:5d:d3:8946:67:bf:52:af:c3:17:0c username@localhost
Generating RSA keys:
Key generation complete.

会在用户目录~/.ssh/产生两个文件，id_rsa，id_rsa.pub
二，把linux100主机上的id_rsa.pub文件拷贝到linux200主机的root用户主目录下的.ssh目录下,并且改名为 authorized_keys
即：
/root/.ssh/authorized_keys
这样在linux100主机上使用scp命令复制文件到linux200上将不提示输入密码了，直接复制了。

反之亦然！

多主机认证，需要将id_rsa.pub先改名，在使用cat authorized_keys1.pub >>　authorized_keys 追加即可