ntp logging
ntp authentication-key 1999 md5 1999
ntp authenticate
ntp trusted-key 1999
ntp source lo0
ntp server 213.0.113.2 version 3 prefer source lo0 key 1999
ntp peer 213.0.113.1 version 3 prefer source lo0 key 1999
!
key chain 1999
 key 1999
  key-string s3cureNTP