3 ms·
It tests primality of numbers greater than the number corresponding to the input image by incrementing. So it's deterministic.
by progval 9y ago
It tests primality of numbers greater than the number corresponding to the input image by incrementing. So it's deterministic.
- Cyberdog 9y agoIncrementing… So pixels at the bottom right of the image are the most likely to be flipped from the source image. Interesting. (Edit: Assuming big-endianness and left-to-right, top-to-bottom printing of the pixels/bits) Nonetheless, yes, using this to create security keys would probably be a good way to lose your bitcoin. :D
- ars 9y agoClearly the current implementation is not enough, but I wonder if there is a way to do this properly with actual security, and yet be reproducible for a normal human (we can assume the same camera and lighting). Maybe some kind of marker in the image that is used for cropping and scaling? Being able to see a particular image, and at a particular time of day (or indoors I guess), would definitely be an interesting security key. (Hollywood: feel free to take this idea and do it badly :)
- esnard 9y agoActually it's decrementing: https://github.com/geonnave/primg/blob/master/index.html#L82 https://github.com/geonnave/primg/blob/master/index.html#L82 I guess it could change the whole image if the last pixels are "000...000", which happens when the top-left corner has an opposite color to the bottom-right one. This image can't be "primed" correctly, for example: https://i.imgur.com/ms3sXtF.png https://i.imgur.com/ms3sXtF.png