Challenge "Holographic Encryption — Part 2"  

  By: admin on April 7, 2017, 10:29 p.m.

Holographic encryption can be performed by employing encryption masks which alter the field before propagation. This makes the image

unrecognizable when recorded. You are given three holograms that represent the cipher image and three plain images and their holograms which were encrypted with the same encryption masks.

 Last edited by: admin on Oct. 31, 2021, 2:55 a.m., edited 1 time in total.

Re: Challenge  

  By: Veselovský on April 11, 2017, 11:28 a.m.

I found masks that decrypt all three holograms to the given three plaintexts, but when I used the same masks to decrypt challenge hologram I got nonsense. How it could be? The description says all four plaintexts were encrypted with the same masks.

Can you confirm correctness of the challenge?

Re: Challenge  

  By: nicosPavlov on April 12, 2017, 2:44 a.m.

This is indeed weird, but I checked the challenge, and as far as I can see, everything seems fine. Are you sure that your masks can exactly recover the given plaintexts?

Re: Challenge  

  By: Veselovský on April 12, 2017, 8:12 a.m.

My masks are not exact, but recovered plaintexts are readable in all three test images except the fourth one. Anyway, I will try to find better masks.

Re: Challenge  

  By: nicosPavlov on April 12, 2017, 8:20 a.m.

My masks are not exact…

Then what is happening is expected. Masks providing only approximate solutions of known plaintexts are not necessarily expected to decrypt any given input.

Re: Challenge  

  By: AnLeRo on July 12, 2017, 1:03 p.m.

The c source code in the additional zip file has been updated. The values in decryption were not exact, but it was always possible to solve the challenge, because nevertheless the signal was fully recognisable.

Best regards

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