Instructions
Approach the door control to decipher whether or not it is hack-friendly. If it is, a hack prompt will appear.
Press the button displayed in the hack prompt to open your hack screen.
Watch the needle on the meter carefully and try to stop it over the green or blue zone. To stop the needle, press "X" on the control pad.
Access the hack screen and select "Buy Out" to buy out the hack without going through the needle process. This is useful if you are at a difficult part of the game and do no wish to risk landing the needle in the incorrect color zone, but bare in mind that it can cost quite an large amount of cash.
Shoot hack darts, or auto hack darts, at the door lock from a distance if you have access to a hack tool. This technique is useful if the door is guarded.