I was trying to work out the security of an system that used the polarized LCD panel over an OLED display (the point being that you can only block certain pixels) and the pixels are either on or off (white or bleck). When the device is enabled someone a random key (lets aim for the best, one time pad quality) is generated that will block a random set of pixels and allow others to pass through unaffected. What is shown is the original display with some pixels blocked off. The blocked off pixels are known only by the content generator and the filter (not the device containing the OLED display). My question is how do I model this system in order to determine what sort its cryptographic quality.

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    $\begingroup$ What system are you trying to devise? There's HDCP that protects high-definition digital video signal from being intercepted and transcoded. Are you trying to block some kind of "analog hole"? $\endgroup$
    – DannyNiu
    Apr 13 '21 at 1:19
  • $\begingroup$ I conjure pry bar & hammer and yank off the LCD panel, thus directly reading the OLED. This might be a valid side channel attack given that the OLED information is physically obscured and not itself cryptographically protected. $\endgroup$
    – Paul Uszak
    Apr 13 '21 at 10:26
  • $\begingroup$ 1) How big is the key? 2) How is it transferred to the OLED device? 3) What is the mathematical relationship between the complexity of the block out pixels and the key? 4) Who are you protecting the information from - the North Koreans or your kids? $\endgroup$
    – Paul Uszak
    Apr 13 '21 at 10:31
  • $\begingroup$ Could you describe what you exactly want to achieve with this, and what your security claims are? We cannot make up your security claims. $\endgroup$
    – Maarten Bodewes
    Apr 13 '21 at 19:38

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