Like not the old key system that is hollow in the middle but think of it like a solid wood broom handle and near the tip of the handle two grooves are cut into it. That's what that image here looked like to me off Kryptonites website which confused me. http://www.kryptonitelock.com/inetis...s_item&pgrp=20
Now when I look at your image above of the OnGuard keys it looks flat and two sided lazer cut. That is what I meant by a flat key before. Sorry for the confusion. I was just confused because the manufacters website keys looked like it was circular locks.
The only two companies that distribute "gold" rated locks to the majority of bike stores in the USA are OnGuard and Kryptonite. Their "gold" level locks use essentially identical keys...these are locks that would take even a skilled pro a very long time to pick. As a result, a "real world" crook walk past a bike that has a "gold" rated u-lock and he will look for bikes using cable locks, or U-locks from fake lock companies such as Master lock.
Look at the "gold" rated locks tested at Soldsecure: