News for hackers. Stuff that matters.

A comment on Why does Numbers hide a huge PNG file in exported Excel sheets?. Parent comment

Re:Why does Numbers hide a huge PNG file in exported Excel s... by UnoriginalGuy on Monday August 18, 2014 @09:39AM (#8192535)
Or more simply, just MD5 them from two machines and see if the hashes (and sizes) match. It is actually quite hard to find hidden text in "random" images. Quite easy to tell if they're identical always however...
[ Parent | on HN ]
Re:Why does Numbers hide a huge PNG file in exported Excel s... by DanBC on Monday August 18, 2014 @10:03AM (#8192629)
Most steganography is trivially easy to detect. Good steganography needs a lot of cover data and better systems than manipulating the LSB.
[ Parent | on HN ]
Re:Why does Numbers hide a huge PNG file in exported Excel s... by nitrogen on Monday August 18, 2014 @10:17AM (#8192690)
If the distribution of bits in an encrypted stream is indistinguishable from normal image dithering, wouldn't encrypted steganography be hard to detect?

It wouldn't survive any lossy image transformations, though.

[ Parent | on HN ]
Re:Why does Numbers hide a huge PNG file in exported Excel s... by MichaelGG on Monday August 18, 2014 @10:22AM (#8192713)
Steganography on normal pictures. If the picture is just random pixels then it would not be detectable.
[ Parent | on HN ]
Re:Why does Numbers hide a huge PNG file in exported Excel s... by DanBC on Tuesday August 19, 2014 @01:46PM (#8198717)
Randomness is something that cryptographers have spent a lot of time studying.

Introducing non-random data into a random data stream is easy to find unless you're very careful about the amounts of data-to-be-hidden and cover-data.

[ Parent | on HN ]
Re:Why does Numbers hide a huge PNG file in exported Excel s... by MichaelGG on Tuesday August 19, 2014 @06:07PM (#8200084)
If you encrypt the data first, then you're inserting "random" data as far as analysis goes.
[ Parent | on HN ]
Re:Why does Numbers hide a huge PNG file in exported Excel s... by hamed_benz on Wednesday August 20, 2014 @03:58AM (#8201453)
salam
[ Parent | on HN ]