以下是简单的操作步骤：

1）先添加一个维护账号：adduser msa
2）然后su - msa

cd /home/msa/

mkdir .ssh

cd .ssh
3）ssh-keygen -t rsa
指定密钥路径和输入口令之后，即在/home/msa/.ssh/中生成公钥和私钥：id_rsa id_rsa.pub。期间要设置秘钥密码：333444，证书登陆时要用到。

id_rsa 是客服端要用的证书
4）cat id_rsa.pub >> authorized_keys至于为什么要生成这个文件，因为sshd_config里面写的就是这个。然后chmod 400 authorized_keys，稍微保护一下。

5）用psftp把把id_rsa拉回本地，然后把服务器上的id_rsa和id_rsa.pub干掉

6）配置/etc/ssh/sshd_config

Protocol 2

#ServerKeyBits 1024

#PermitRootLogin no  #禁止root登录而已，与本文无关，加上安全些#以下三行没什么要改的，把默认的#注释去掉就行了

RSAAuthentication yes

PubkeyAuthentication yes

AuthorizedKeysFile    .ssh/authorized_keys

PasswordAuthentication no

#PermitEmptyPasswords no

7）重启 sshd      /sbin/service sshd restart

8）用 SecureCRTPortable 软件 publicKey方式登陆

9)配置文件：

#	$OpenBSD: sshd_config,v 1.80 2008/07/02 02:24:18 djm Exp $


# This is the sshd server system-wide configuration file.  See
# sshd_config(5) for more information.


# This sshd was compiled with PATH=/usr/local/bin:/bin:/usr/bin


# The strategy used for options in the default sshd_config shipped with
# OpenSSH is to specify options with their default value where
# possible, but leave them commented.  Uncommented options change a
# default value.


#Port 22
Port 220 #端口
#ListenAddress 0.0.0.0
#ListenAddress ::


# Disable legacy (protocol version 1) support in the server for new
# installations. In future the default will change to require explicit
# activation of protocol 1
Protocol 2


# HostKey for protocol version 1
#HostKey /etc/ssh/ssh_host_key
# HostKeys for protocol version 2
#HostKey /etc/ssh/ssh_host_rsa_key
#HostKey /etc/ssh/ssh_host_dsa_key


# Lifetime and size of ephemeral version 1 server key
#KeyRegenerationInterval 1h
#ServerKeyBits 1024


# Logging
# obsoletes QuietMode and FascistLogging
#LogLevel INFO


# Authentication:


#LoginGraceTime 2m
#StrictModes yes
#MaxAuthTries 6
#MaxSessions 10


RSAAuthentication yes	#-----------去掉注释------------------
PubkeyAuthentication yes	#-----------去掉注释------------------
AuthorizedKeysFile	.ssh/authorized_keys	#-----------去掉注释------------------
#AuthorizedKeysCommand none
#AuthorizedKeysCommandRunAs nobody


# For this to work you will also need host keys in /etc/ssh/ssh_known_hosts
#RhostsRSAAuthentication no
# similar for protocol version 2
#HostbasedAuthentication no
# Change to yes if you don't trust ~/.ssh/known_hosts for
# RhostsRSAAuthentication and HostbasedAuthentication
#IgnoreUserKnownHosts no
# Don't read the user's ~/.rhosts and ~/.shosts files
#IgnoreRhosts yes


# To disable tunneled clear text passwords, change to no here!
#PermitEmptyPasswords no


# Change to no to disable s/key passwords
#ChallengeResponseAuthentication yes
ChallengeResponseAuthentication no


# Kerberos options
#KerberosAuthentication no
#KerberosOrLocalPasswd yes
#KerberosTicketCleanup yes
#KerberosGetAFSToken no
#KerberosUseKuserok yes


# GSSAPI options
#GSSAPIAuthentication no
GSSAPIAuthentication yes
#GSSAPICleanupCredentials yes
GSSAPICleanupCredentials yes
#GSSAPIStrictAcceptorCheck yes
#GSSAPIKeyExchange no


# Set this to 'yes' to enable PAM authentication, account processing, 
# and session processing. If this is enabled, PAM authentication will 
# be allowed through the ChallengeResponseAuthentication and
# PAM authentication via ChallengeResponseAuthentication may bypass
# If you just want the PAM account and session checks to run without
# and ChallengeResponseAuthentication to 'no'.
#UsePAM no
UsePAM yes


# Accept locale-related environment variables
AcceptEnv LANG LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES
AcceptEnv LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT
AcceptEnv LC_IDENTIFICATION LC_ALL LANGUAGE
AcceptEnv XMODIFIERS


#AllowAgentForwarding yes
#AllowTcpForwarding yes
#GatewayPorts no
#X11Forwarding no
X11Forwarding yes
#X11DisplayOffset 10
#X11UseLocalhost yes
#PrintMotd yes
#PrintLastLog yes
#TCPKeepAlive yes
#UseLogin no
#UsePrivilegeSeparation yes
#PermitUserEnvironment no
#Compression delayed
#ClientAliveInterval 0
#ClientAliveCountMax 3
#ShowPatchLevel no
#PidFile /var/run/sshd.pid
#MaxStartups 10:30:100
#PermitTunnel no
#ChrootDirectory none


# no default banner path
#Banner none


# override default of no subsystems
Subsystem	sftp	/usr/libexec/openssh/sftp-server


# Example of overriding settings on a per-user basis
#Match User anoncvs
#	X11Forwarding no
#	AllowTcpForwarding no
#	ForceCommand cvs server
UseDNS no
AddressFamily inet
PermitRootLogin yes
SyslogFacility AUTHPRIV
#PasswordAuthentication yes
PasswordAuthentication no	#-----------禁止账号登陆------------------