{"id":11354,"date":"2007-01-08T12:30:57","date_gmt":"2007-01-08T12:30:57","guid":{"rendered":"http:\/\/blogs.adobe.com\/jnackdev\/2007\/01\/decoding-scrambled-pixels.html"},"modified":"2007-01-08T12:30:57","modified_gmt":"2007-01-08T12:30:57","slug":"decoding_scrambled_pixels","status":"publish","type":"post","link":"https:\/\/jnack.com\/blog\/2007\/01\/08\/decoding_scrambled_pixels\/","title":{"rendered":"Decoding scrambled pixels"},"content":{"rendered":"<p>Removing data from a digital file is sometimes easier said than done. <a href=\"http:\/\/en.wikipedia.org\/wiki\/Redaction\">Redacting<\/a> PDFs has sometimes proven tricky (something the Acrobat team has <a href=\"http:\/\/blogs.adobe.com\/acrolaw\/2006\/10\/acrobat_8_new_f_1.html\">worked to address<\/a>), and now <a href=\"http:\/\/dheera.net\/projects\/blur.php\">a research report<\/a> notes methods for unscrambling numbers or text that have been obscured via simple Photoshop tricks. [<a href=\"http:\/\/www.boingboing.net\/2007\/01\/07\/unblurring_mosaicblu.html\">Via<\/a>] <\/p>\n<p>I asked a few Photoshop engieneers for comments &amp; got some useful nuggets:<\/p>\n<ul>\n<li><a href=\"http:\/\/blogs.adobe.com\/jnack\/2006\/12\/malepattern_bal.html\">Gregg Wilensky<\/a> says, &quot;The ability to recover text that is blurred is limited by the amount of<br \/>\nnoise in the image (and knowledge of the blurring function). So, adding<br \/>\na bunch of noise to the image is better, but still not foolproof. I<br \/>\nwould suggest completely replacing the text with noise and blurring that<br \/>\n(for aesthetics).&quot;<\/li>\n<li><a href=\"http:\/\/www.macworld.com\/2002\/04\/features\/photoshop\/index1.php\">Jerry Harris<\/a> notes, &quot;Having a known set of limited targets, OCR numbers in his example, makes the<br \/>\nreconstruction task a bit more realistic in terms of useful results than<br \/>\nmost.&quot;<\/li>\n<li>And <a href=\"http:\/\/blogs.adobe.com\/jnack\/2005\/11\/todor_and_jeff.html\">Todor Georgiev<\/a> writes, &quot;Using a known set of blur kernels (those in Photoshop!),<br \/>\nand a known set of targets, limits the set of possible outcomes<br \/>\nand makes this technique work. But slightly change lighting<br \/>\nand\/or use custom blur filter, and your data is safe.&quot;\n<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Removing data from a digital file is sometimes easier said than done. Redacting PDFs has sometimes proven tricky (something the Acrobat team has worked to address), and now a research report notes methods for unscrambling numbers or text that have been obscured via simple Photoshop tricks. [Via] I asked a few Photoshop engieneers for comments [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[47],"tags":[],"_links":{"self":[{"href":"https:\/\/jnack.com\/blog\/wp-json\/wp\/v2\/posts\/11354"}],"collection":[{"href":"https:\/\/jnack.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jnack.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jnack.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jnack.com\/blog\/wp-json\/wp\/v2\/comments?post=11354"}],"version-history":[{"count":0,"href":"https:\/\/jnack.com\/blog\/wp-json\/wp\/v2\/posts\/11354\/revisions"}],"wp:attachment":[{"href":"https:\/\/jnack.com\/blog\/wp-json\/wp\/v2\/media?parent=11354"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jnack.com\/blog\/wp-json\/wp\/v2\/categories?post=11354"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jnack.com\/blog\/wp-json\/wp\/v2\/tags?post=11354"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}