A security conference, which is covered in the above article on CPE's is one CPE per hour of the conference. Depending on what you are counting these CPE's for, and what the security conference was specifically about they would most likely be A CPE's for you or possibly B CPE's.
To confirm, @tsutherburg is correct. You may submit 1 CPE per hour of attendance for attending a conference. If the conference was domain related, you may submit as Group A. If not, but professional development, Group B.