paranoiq

#ssh-rsa AAAA[0-9A-Za-z+/]+[=]{0,3} ([^@]+@[^@]+)#

// this is the most simple case. see more complete regexps in coments below

// http://generator.my-addr.com/generate_ssh_public_rsa_key-private_rsa_key-ssh_pair_online_tool.php

// https://help.ubuntu.com/community/SSH/OpenSSH/Keys

// http://www.ietf.org/rfc/rfc4716.txt