Neither of them require a special digit after the code, or an enter key, and both of them have entry codes with repeating digits.
I suppose with 10 transparent markers that are distinguishable under detailed inspection (such as fluorescing to different colors under UV light), you could even work out the right order on the first try: "traces of orange have transferred to 3 other keys, so the orange key was pressed first; traces of green to 2 other... (etc.)"
How about "use something random, change the keys before they wear down, and wipe them before and after use if you're paranoid."
4 presses out of 10 options, not allowing duplicates, and order is significant: 5,040 options.
It's less certainly, but not dramatically.
4 presses out of 10 options, not allowing duplicates, and order is not significant: 210. That, I would call a dramatic reduction.
In a typical 10 button number lock order is not important, and you can choose from 1 to 10 presses: 1024 options.
http://coder.bsimmons.name/blog/2009/09/cracking-a-lock-in-h...
We must have been reading the same articles on reddit which lead us to the same tengentially-related wikipedia page or something.
So why would anyone make keypads without them? Ease of use over security?
Trying to find a real reason to buy an infrared meter..
