# rpm --import http://www.jasonlitka.com/media/RPM-GPG-KEY-jlitka 

# vi /etc/yum.repos.d/CentOS-Base.repo 增加下面信息

[utterramblings]
name=Jason's Utter Ramblings Repo
baseurl=http://www.jasonlitka.com/media/EL$releasever/$basearch/
enabled=1
gpgcheck=1
gpgkey=http://www.jasonlitka.com/media/RPM-GPG-KEY-jlitka

yum update php -y
yum install libmcrypt -y