Mac 升级到最新操作系统ssh加密方式和gitlub不一样，导致不能git pull 如：mac是md5加密方式，gitlut是aes-256-cbc加密方式 解决方法如下
A coworker of mine was reporting an issue with SSH after updating to Mac OS X High Sierra.
$ ssh server-alias-hostname
Unable to negotiate with 192.168.1.5 port 22: no matching cipher found. Their offer: blowfish-cbc,aes256-cbc打开对应路径，加入如下配置即可
It turns out that the system is configured to use certain ciphers within/etc/ssh/ssh_config.
You can adjust your local configuration within ~/.ssh/configto make sure that the ciphers supported by your local client match one of the ones offered by the remote server.
# ~/.ssh/config
Host *
SendEnv LANG LC_*
Ciphers +aes256-cbc