9 ms·
That level of blurring is almost certainly insufficient to actually redact the information, as discussed in http://dheera.net/projects/blur.php http://dheera.ne
by Robin_Message 15y ago
That level of blurring is almost certainly insufficient to actually redact the information, as discussed in http://dheera.net/projects/blur.php http://dheera.net/projects/blur.php (discussed here http://news.ycombinator.com/item?id=1939607 http://news.ycombinator.com/item?id=1939607)
- verroq 15y agoI don't think so, it'd take way too long to dictionary attack/bruteforce the missing 64 x 9 characters of the blurred image. Which gives 64 ^ (64 x 9) combinations judging from the base64 encoding. That is assuming you have the blurring algorithm and font perfect.
- meric 15y agoWhat prevents you from doing it with only 5 letters at a time?
- binarymax 15y agoNo - we already know that the same blurring algorithm was used for all the characters. The font can be found and matched quickly and you only need to calibrate the blur for one character. The blurring algorithm will give you a pixel perfect representation for character match so its more on the order of 64 * 600 (600 is the approx number of chars blurred). This could be cracked in a day or less by someone motivated enough.
- verroq 15y agoHow do you know that blurring one character produces the same effect as blurring two characters close together?
- jrockway 15y agoYou don't need to know this. You make an image of the text for every combination possible, apply the blur algorithm, and see which one is a pixel-perfect match for to the image on the web site. Or rather, you don't do this, you write a program to do it :)
- verroq 15y agoBut you'll have to go through 64 ^ (64 x 9), combinations which will take years which was what I said in the first post.
- RichieB2B 15y agoNo unblurring required. Just some 3DES brute forcing. http://pastebin.com/aJ5rzVY0 http://pastebin.com/aJ5rzVY0