&nbrs;Beyond Resolution

 


▩ [ DCT encryption ] 
HOW NOT TO BE READ* [ a recipe using DCT ENCRYPTION ]
<href: Hito Steyerl: How Not to Be Seen, 2013>

The legibility of an encrypted message does not just depend on the complexity of the encryption algorithm, but also on the placement of the data of the message. Here they are closely connected to resolutions: resolutions determine what is read and what is unseen or illegible.

DCT ENCRYPTION (2015) uses the aesthetics of JPEG macroblocks to mask its secret messages on the surface of the image, mimicking error. The encrypted message, hidden on the surface is only legible by the ones in the know; anyone else will ignore it like dust on celluloid.

While the JPEG compession consists of 6 steps, the basis of the compression is DCT, or Discrete Cosine Transform. During the final, 6th step of the JPEG compression, entropy coding, a special form of lossless data compression, takes place. Entropy coding involves the arranging the image components in a "zigzag" order, using run-length encoding (RLE) to group similar frequencies together.
How Not to be Read, a recipe using DCT:

  • Choose a lofi JPEG base image on which macroblocking artifacts are slightly apparent. This JPEG will serve as the image on which your will write your secret message.
  • If necessary, you can scale the image up via nearest neighbour interpolation, to preserve hard macroblock edges of the base image.
  • Download and install the DCT font
  • Position your secret message on top of the JPEG. Make sure the font has the same size as the macroblock artifacts in the image
  • Flatten the layers (image and font) back to a JPEG. This will make the text no longer selectable and readable as copy and paste data.


︎ for the #3D Additivist Cookbook.
︎ DCT won the Crypto Desgin Challenge Award in 2015.

A Discrete Cosine Transform simplified to make a monochrome .ttf font and iRD logo. In the logo RLE 010 000 - 101 1111 signifies the key to the DCT encryption: 010 000 - 101 1111 are the binary values of the 64 most used ASCII glyphs, which are then mapped onto the DCT in a zig zag order (following RLE).

Discrete Cosine Transform (DCT) was first conceived for the Crypto Design Challenge

A recipe using DCT” was released in the #Additivism cookbook.



Mesmerized by the screen, focusing on the moves of a next superhero, I was conditioned to ignore the dust imprinted on the celluloid or floating around in the theater, touching the light of the projection and mingling itself with the movie.

The dust – micro-universes of plant, human and animal fibers, particles of burnt meteorites, volcanic ashes, and soil from the desert – could have told me stories reaching beyond my imagination, deeper and more complex than what resolved in front of me, reflecting from the movie screen.
… But I never paid attention.

I focused my attention to where I was conditioned to look: to the feature, reflecting from the screen. All I saw were the images. I did not see the physical qualities of the light nor the materials making up its resolution; before, behind, and beyond the screen.

Decennia of conditioning the user to ignore these visual artifacts and to pay attention only to the overall image has changed these artifacts into the ultimate camouflage for secret messaging. Keeping this in mind, I developed DCT.

Premise of DCT is the realisation that the legibility of an encrypted message does not just depend on the complexity of the encryption algorithm, but also on the placement of the message. This encrypted message, hidden on the surface of the image, is only legible by the ones in the know; anyone else will ignore it. Like dust on celluloid, DCT is mimics JPEG error. It appropriates the algorithmic aesthetics of JPEG macroblocks to stenographically mask a secret message, mimicking error. The encrypted message, hidden on the surface of the image, is only legible by the ones in the know.