一、为了在Linux下使用scp的时候不需要输入密码，采用ssh另一种用密钥对来验证的方式 。
1、使用ssh-keygen 命令生成密钥。生成过程中，除了输入密码外，其他都选择默认的值：回车即可。
[root@xxx root]# ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Created directory '/root/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
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:
e0:f0:3b:d3:0a:3d:da:42:01:6a:61:2f:6c:a0:c6:e7 root@xxx
[root@xxx root]#