Secret editing of EXIF data for photographs using freeware
 

Can you give me advice on how best to modify EXIF info for digital photos
so that it is hard for a recipient to immediately know that the EXIF data
was modified?

Here is the manual procedure I use today to replace/modify EXIF data:
0) Starting with known good EXIF data in a jpg file called "old.jpg".

1) Replace the exif data: c:\> jhead -te old.jpg new.jpg

So as not to trip up with the EXIF size information, I reset it:
2) Reset image size data: exifer: EXIF/IPTC->Update EXIF image size values

Likewise with the EXIF thumbnails (which trip up a lot of people):
3) Remove old exif thumbnail: exifer: EXIF/IPTC->Thumbnail->Remove
thumbnail
4) Create new exif thumbnail: exifer: EXIF/IPTC->Thumbnail->Create
thumbnail

But, what else am I missing that will be a tell tale sign that the EXIF
data was modified? Am I missing anything obvious that will trip me up?

For example, how/should do I modify those other telltale EXIF info fields?
* ShutterSpeedValue
* SubjectDistance
* ImageNumber
* OwnerName
* Software
etc.

Re: Secret editing of EXIF data for photographs using freeware
 

> For example, how/should do I modify those other telltale EXIF info fields?
> * ShutterSpeedValue
> * SubjectDistance
> * ImageNumber
> * OwnerName
> * Software

I forgot to mention that exifer doesn't edit these fields so how my
question is two fold (how + what).

a) How do we edit EXIF fields such as "software" and "ownername"?

b) What other EXIF fields are dead giveaways that the EXIF was modified?

Re: Secret editing of EXIF data for photographs using freeware
 

On Wed, 25 Jun 2008 16:25:45 -0700, EXIF Info wrote:

>> For example, how/should do I modify those other telltale EXIF info
>> fields? * ShutterSpeedValue
>> * SubjectDistance
>> * ImageNumber
>> * OwnerName
>> * Software
>
> I forgot to mention that exifer doesn't edit these fields so how my
> question is two fold (how + what).
>
> a) How do we edit EXIF fields such as "software" and "ownername"?
>
> b) What other EXIF fields are dead giveaways that the EXIF was modified?

Try taking the pictures yourself.

Dave



--
Registered Linux user # 444770
Tact is the ability to tell a man he has an open mind when he has a
hole in his head.

Re: Secret editing of EXIF data for photographs using freeware
 

On Wed, 25 Jun 2008 16:22:05 -0700, EXIF Info wrote:

> Can you give me advice on how best to modify EXIF info for digital photos
> so that it is hard for a recipient to immediately know that the EXIF data
> was modified?

You can not modify these exif tags because they are permanent in the system
and will always be visable. It can't be done.

Re: Secret editing of EXIF data for photographs using freeware
 

In article <g4E8k.5759$L_.1158@flpi150.ffdc.sbc.com>, Steve
<steve_mulinex@hotmail.com> wrote:
>
> > Can you give me advice on how best to modify EXIF info for digital photos
> > so that it is hard for a recipient to immediately know that the EXIF data
> > was modified?
>
> You can not modify these exif tags because they are permanent in the system
> and will always be visable. It can't be done.

nonsense. there are numerous tools that can edit exif data, exiftool
being one of the best.

Re: Secret editing of EXIF data for photographs using freeware
 

Steve wrote:
> On Wed, 25 Jun 2008 16:22:05 -0700, EXIF Info wrote:
>
>> Can you give me advice on how best to modify EXIF info for digital photos
>> so that it is hard for a recipient to immediately know that the EXIF data
>> was modified?
>
> You can not modify these exif tags because they are permanent in the system
> and will always be visable. It can't be done.


Of course you can. I have had occasion to do it, usually when setting
someone up. You need more than photographic skills and software though,
you need to be at least a little bit hacker inclined.

PK

Re: Secret editing of EXIF data for photographs using freeware
 

On Wed, 25 Jun 2008 16:22:05 -0700, EXIF Info wrote:
>
> Can you give me advice on how best to modify EXIF info for digital photos
> so that it is hard for a recipient to immediately know that the EXIF data
> was modified?

You can try
ExifTool
http://www.sno.phy.queensu.ca/~phil/exiftool/
With this Windows GUI
http://freeweb.siol.net/hrastni3/fot...xiftoolgui.htm

or try this Windows program
http://www.photome.de/

Re: Secret editing of EXIF data for photographs using freeware
 

EXIF Info wrote:
> Can you give me advice on how best to modify EXIF info for digital photos
> so that it is hard for a recipient to immediately know that the EXIF data
> was modified?
>
> Here is the manual procedure I use today to replace/modify EXIF data:
> 0) Starting with known good EXIF data in a jpg file called "old.jpg".
>
> 1) Replace the exif data: c:\> jhead -te old.jpg new.jpg
>
> So as not to trip up with the EXIF size information, I reset it:
> 2) Reset image size data: exifer: EXIF/IPTC->Update EXIF image size values
>
> Likewise with the EXIF thumbnails (which trip up a lot of people):
> 3) Remove old exif thumbnail: exifer: EXIF/IPTC->Thumbnail->Remove
> thumbnail
> 4) Create new exif thumbnail: exifer: EXIF/IPTC->Thumbnail->Create
> thumbnail
>
> But, what else am I missing that will be a tell tale sign that the EXIF
> data was modified? Am I missing anything obvious that will trip me up?
>
> For example, how/should do I modify those other telltale EXIF info fields?
> * ShutterSpeedValue
> * SubjectDistance
> * ImageNumber
> * OwnerName
> * Software
> etc.

You could just strip the EXIF data altogether...

Re: Secret editing of EXIF data for photographs using freeware
 

EXIF Info wrote:
> Can you give me advice on how best to modify EXIF info for digital photos
> so that it is hard for a recipient to immediately know that the EXIF data
> was modified?
>
> Here is the manual procedure I use today to replace/modify EXIF data:
> 0) Starting with known good EXIF data in a jpg file called "old.jpg".
>
> 1) Replace the exif data: c:\> jhead -te old.jpg new.jpg
>
> So as not to trip up with the EXIF size information, I reset it:
> 2) Reset image size data: exifer: EXIF/IPTC->Update EXIF image size values
>
> Likewise with the EXIF thumbnails (which trip up a lot of people):
> 3) Remove old exif thumbnail: exifer: EXIF/IPTC->Thumbnail->Remove
> thumbnail
> 4) Create new exif thumbnail: exifer: EXIF/IPTC->Thumbnail->Create
> thumbnail
>
> But, what else am I missing that will be a tell tale sign that the EXIF
> data was modified? Am I missing anything obvious that will trip me up?
>
> For example, how/should do I modify those other telltale EXIF info fields?
> * ShutterSpeedValue
> * SubjectDistance
> * ImageNumber
> * OwnerName
> * Software
> etc.

The best way is to strip these data out. Many image handling programs
don't even attempt to save them, and those which know how to usually
have the option to strip them.

Making fake data is harder, some points to consider:

- camera make/model:

- you have to find the actual string used by the target model (which
may be different depending on continent).

- for SLRs, some makes (Nikon, at least) include technical data on
the lens used: min/max focal length and associated apertures.

- other data should be compatible with that different model:
original image size and aspect ratio, ISO, aperture, speed, focal length
and focal length/equivalent 35mm focal length ratio (physical sensor
size), flash mode, various data (scene mode), exif version, and possibly
the format of some fields.

- date/time/position:

- should be reasonably consistent with picture (lighting and sun
position, weather...)(and this is in several places).

- With GPS one can check things out on GoogleEarth (it is even
possible to crosscheck these mountains in the background)

- technical shoot data:

- an expert eye will have a rough idea of the focal length used. You
can cheat a bit there, though (1.5x both sides), but if you have the
subject distance in the Exif, it will be harder. I don't know if DSLRs

- you have to remain within a reasonably consistent set of values
for focal length, aperture, sensor size, and depth of field (and of
course camera/lens)

Good luck :-)






















[Image]
Make = Panasonic
Model = DMC-FZ8
Orientation = top/left
Software = Ver.1.0
Date Time = 2007-08-18 10:43:36

[Camera]
Exposure Time = 1/200"
F Number = F5
Exposure Program = Normal program
ISO Speed Ratings = 100
Exif Version = Version 2.21
Date Time Original = 2007-08-18 10:43:36
Date Time Digitized = 2007-08-18 10:43:36
Exposure Bias Value = ±0EV
Max Aperture Value = F2.83
Metering Mode = Pattern
Light Source = Fine weather
Flash = Flash did not fire, compulsory flash mode
Focal Length = 55.2mm
Maker Note = 6786 Byte
Flashpix Version = Version 1.0
Color Space = sRGB
Exif Image Width = 3072
Exif Image Height = 2304
Sensing Method = One-chip color area sensor
File Source = DSC
Scene Type = A directly photographed image
Custom Rendered = Normal process
Exposure Mode = Auto exposure
White Balance = Manual white balance
Digital Zoom Ratio =
Focal Length In 35mm Film = 331mm
Scene Capture Type = Normal
Gain Control = None
Contrast = Normal
Saturation = Normal
Sharpness = Normal

[Thumbnail Info]
Orientation = top/left

[Thumbnail]
Thumbnail = 160 x 120







--
Bertrand

Re: Secret editing of EXIF data for photographs using freeware
 

On Wed, 25 Jun 2008 23:17:18 -0700 'Matt Ion'
wrote this on alt.comp.freeware:

>You could just strip the EXIF data altogether...

That's easy but methinks the OP wants to modify it for some reason
or other, which he hasn't stated.


--
"All truth passes through three stages.
First, it is ridiculed, second it is violently opposed,
and third, it is accepted as self-evident"
(Arthur Schopenhauer)