4 ms·

Color me extremely skeptical until I see a rigorous security proof. Fun little schemes like this are a dime a dozen, and often are essentially useless for any r

Color me extremely skeptical until I see a rigorous security proof. Fun little schemes like this are a dime a dozen, and often are essentially useless for any real application.

NLips 14y ago
FTA: "Wu and co make no claims about its potential security but there is clearly room for further exploration here. "
- swordswinger12 14y ago
  They need to be more careful about using the word 'cryptography' then. Sure, crypto people and informed laypersons know this is hopelessly insecure, but all it takes is one overzealous intern implementing this in a banking application to cause a huge problem.
  - NLips 14y ago
    The only word I see is "encrypt", but regardless, this IS cryptography - converting to a code. You can encrypt with a Ceaser cipher, though it's not terribly secure.
breckinloggins 14y ago
Indeed. It's a clever convolution filter, but all you have to do is look at the resulting image to see some weaknesses. The naive tiling approach is even worse. So let's say I wanted to find the image on the Internet that most likely represented the original of some "sudoku encrypted" image? 1. Throw out any images that are strictly smaller than the cipher image. This technique doesn't do any compression 2. Throw out any images that are larger or of a significantly given aspect ratio than the cipher image, based on how many more pixels could have possibly been added to complete the sudokus on each edge 3. Compare the color histogram or some precise additive hash of color values from the cipher image to some candidate image. If the values differ, reject the candidate. This should work because the algorithm as described only seems to shuffle pixels locally in a tile. So the convolution should still have the exact same overall color frequencies. Edges where some pixels might have been filled in may have to be treated differently. 4. Continue this process until you have a reasonably short result of candidate images You could easily solve many of these issues by using the filter to shift both space and color values and by recursively applying the shuffling process to larger and larger blocks of the image, but certainly the procedure as described in the linked article sounds suspect. I could actually see this being researched for compression as well as encryption. Maybe try some sudoku convolutions and see if they compress better. If so, compress that image along with the sudoku solution. I doubt it would work but it might be worth a look.

Color me extremely skeptical until I see a rigorous security proof. Fun little schemes like this are a dime a dozen, and often are essentially useless for any real application.

NLips 14y ago

FTA: "Wu and co make no claims about its potential security but there is clearly room for further exploration here. "

swordswinger12 14y ago
They need to be more careful about using the word 'cryptography' then. Sure, crypto people and informed laypersons know this is hopelessly insecure, but all it takes is one overzealous intern implementing this in a banking application to cause a huge problem.
- NLips 14y ago
  The only word I see is "encrypt", but regardless, this IS cryptography - converting to a code. You can encrypt with a Ceaser cipher, though it's not terribly secure.

breckinloggins 14y ago

Indeed. It's a clever convolution filter, but all you have to do is look at the resulting image to see some weaknesses. The naive tiling approach is even worse. So let's say I wanted to find the image on the Internet that most likely represented the original of some "sudoku encrypted" image? 1. Throw out any images that are strictly smaller than the cipher image. This technique doesn't do any compression 2. Throw out any images that are larger or of a significantly given aspect ratio than the cipher image, based on how many more pixels could have possibly been added to complete the sudokus on each edge 3. Compare the color histogram or some precise additive hash of color values from the cipher image to some candidate image. If the values differ, reject the candidate. This should work because the algorithm as described only seems to shuffle pixels locally in a tile. So the convolution should still have the exact same overall color frequencies. Edges where some pixels might have been filled in may have to be treated differently. 4. Continue this process until you have a reasonably short result of candidate images You could easily solve many of these issues by using the filter to shift both space and color values and by recursively applying the shuffling process to larger and larger blocks of the image, but certainly the procedure as described in the linked article sounds suspect. I could actually see this being researched for compression as well as encryption. Maybe try some sudoku convolutions and see if they compress better. If so, compress that image along with the sudoku solution. I doubt it would work but it might be worth a look.