Venting

[Joep]

Need to vent this. People in my house don't understand my excitement about this. Maybe you won't either

Today I added an option to a utility I wrote to append arbitrary data to a JPEG header.

This is useful to try to repair recovered files that are corrupt and offer no point of reference (JPEG markers) at all. So a binary blob basically. Only makes sense IF entropy is kinda like JPEG data (7.6 - 7.99 bits/byte is what I settled for).

You can glue *any* file to a JPEG header and the tool will strip any byte combinations that violate JPEG specs. So you could for example feed it an MP3 or a ZIP + a valid JPEG file and final result will be a view-able JPEG based on the data in the MP3 or ZIP. It will be a psychedelic mess, non the less a valid JPEG.

Sofar I managed to repair 5 files with somewhat useful images. Owner of the images allowed me to video one repair from photo without any people.

For if you have nothing better to do:

 

[Markverhyden]

Interesting. Is this something that would be used to "tag" a JPG for future recovery purposes? Or part of the process after the fact? Doing some research led me to Cicada 3301. Never heard of it before. Been very fascinating.

 

[GreyWolf]

So something under theses lines..

https://github.com/dbohdan/s2png
https://github.com/leeroybrun/Bin2PNG

For me I want to do something like this but to store data into a video file and restore at will.
https://jabcode.org/

or for my security labels something like this: http://www.warmplace.ru/soft/phonopaper/

For your idea looks great but If I could figure out the best image format to input data I could shove in prime numbers or PI sequence and see what wonders would show up.

Also very old program but might help you in finding header code is TRID http://mark0.net/soft-trid-e.html

Keep up the great work it's with creativity that we find new ways to use and repair things.

 

[Joep]

Heuh?

What did you guys use?

It's a JPEG Repair tool. This guy had recovered JPEGs and they were all corrupt. Most JPEG repair tools try to fix the 'header' which is only a fraction of the file. So does mine but it needs (or needed until now) a start of scan markers which tells where the actual encoded/compressed image data starts.

The files of this guy were binary blobs without any JPEG markers, however entropy of the files looked as if they contained encoded/compressed JPEG data. Does not mean by definition is actually is, a ZIP file I assume would give similar entropy.

So all I did was teach my tool, take valid header and append data of the corrupt file. Then strip that of anything that can upset photo viewers and editors. If that results in something that looks like a picture, probably corrupt then we have a fighting chance.

This was the most boring picture so he allowed me to use it to make a video. The others had girls in them. Video can also help him to repair the rest of his files.

 

[GreyWolf]

Oh OK my apologies I thought you we're attempting a different package method for extracting other data.

 

[Joep]

No apologies needed, in fact I am sorry if that didn't come across too well. Was joke when I asked what you had been using. I will add a wink.

 

[Joep]

Interesting. Is this something that would be used to "tag" a JPG for future recovery purposes? Or part of the process after the fact? Doing some research led me to Cicada 3301. Never heard of it before. Been very fascinating.

Mark this an incorrectly recovered JPEG.