Security Cameras are used to keep tab on the Triads, and you need to go around and hack them to help the Hong Kong Police bust the drug dealers. There are a total of 26 cameras in the game, with 18 of those located at Drug Bust locations (pale blue shield icons on map), and two more (one in the "Bad Luck" story mission and another during the dating side mission for Not-Ping), which means there are 6 cameras that you have to find. Security Cameras are unlocked during the Popstar police case, which is unmissable in the story.
To hack a Security Camera, you must find the control panel nearby. Once you find it, you have to input a 4-digit code to hack it. The thing to remember is that the code has numbers ranging from 0 to 9, with only each number being used once (meaning there won't be two 9s in the code, for example). All codes are randomly generated, meaning even if you hack the same camera twice, it will be a different code.
A number with a red square is not in the code at all, a yellow circle indicates the number is in the wrong position, while a green number means it's perfect and doesn't need changed. The best thing to do is start with 0, 1, 2 and 3 and go through the digits in order. You only have a few chances to guess the right code, so make sure you don't reuse red numbers and change the positions of yellow ones.
NOTE - Finishing the dating side mission for Not-Ping will unlock the locations for the Security Cameras on your mini-map.
