I get this question a lot... I believe the difficulty level changes depending on how often lock was used, weather and how old it is. In a perfect scenario with a perfect lock....Picking I would put HU64 as the most difficult for most people. The issue is not the lock but the length and thickness of the lishi tool levers. This throws people off as a stiff wafer might feel like it's got some spring to it. So this lock I teach people a slightly different technique in order to not be fooled. Easiest lock to pick and decode? CY24!!!