Secret editing of EXIF data for photographs using freeware

Discussion in 'Digital Photography' started by EXIF Info, Jun 26, 2008.

  1. EXIF Info

    EXIF Info Guest

    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.
     
    EXIF Info, Jun 26, 2008
    #1
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  2. EXIF Info

    EXIF Info Guest

    > 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?
     
    EXIF Info, Jun 26, 2008
    #2
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  3. EXIF Info

    Dave Guest

    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.
     
    Dave, Jun 26, 2008
    #3
  4. EXIF Info

    Steve Guest

    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.
     
    Steve, Jun 26, 2008
    #4
  5. EXIF Info

    nospam Guest

    In article <g4E8k.5759$>, Steve
    <> 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.
     
    nospam, Jun 26, 2008
    #5
  6. EXIF Info

    Penis Kolada Guest

    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
     
    Penis Kolada, Jun 26, 2008
    #6
  7. EXIF Info

    CoMa Guest

    CoMa, Jun 26, 2008
    #7
  8. EXIF Info

    Matt Ion Guest

    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...
     
    Matt Ion, Jun 26, 2008
    #8
  9. EXIF Info

    Ofnuts Guest

    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
     
    Ofnuts, Jun 26, 2008
    #9
  10. EXIF Info

    hummingbird Guest

    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)
     
    hummingbird, Jun 26, 2008
    #10
  11. EXIF Info

    EXIF Info Guest

    On Thu, 26 Jun 2008 10:46:26 +0200, Ofnuts wrote:

    > Making fake data is harder, some points to consider:

    Exactly the point! The false EXIF data needs to roughly match the
    photograph! But how?

    > - date/time/position:
    > - lighting and sun position

    Good point to check the shadows for outdoor shots to see if they match with
    the time the picture was falsly taken. I'll add this to my checklist.

    > - an expert eye will have a rough idea of the focal length used.
    > - if you have the subject distance in the Exif, it will be harder.

    Yes indeed! This is the type of observation I was looking for.
    I try to change the EXIF subject distance to match the photograph but I
    didn't think about the focal length having to match. Are you sure an expert
    could guess the focal length from a photograph?

    > - 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)


    Sensor size? Hmmmmmm.... From any given photograph, how would "sensor size"
    be obvious to a trained observer? I don't know how to fake sensor size.
    What would be rough estimation points for the falsified EXIF?
     
    EXIF Info, Jun 26, 2008
    #11
  12. EXIF Info

    EXIF Info Guest

    On Thu, 26 Jun 2008 10:45:48 +0100, hummingbird wrote:

    >>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.


    The reason is to create a believable yet false EXIF trail instead of no
    EXIF whatsoever.

    That is, the viewer, perhaps thousands of them for any one photograph,
    needs to believe the photograph was taken at the time and place with the
    camera, setting, and lighting conditions that are in the EXIF fields.
     
    EXIF Info, Jun 26, 2008
    #12
  13. EXIF Info

    EXIF Info Guest

    On Thu, 26 Jun 2008 07:51:54 +0200, CoMa wrote:

    > ExifTool
    > http://www.sno.phy.queensu.ca/~phil/exiftool/
    > With this Windows GUI
    > http://freeweb.siol.net/hrastni3/foto/exif/exiftoolgui.htm


    Thank you CoMa! ExifTool + the GUI was able to edit fields that exifer just
    couldn't touch such as "Software" and "Owner Name".

    Interestingly, ExifTool goofed somewhat (I think) in that it allowed
    blanking of "Owner Name" but blanking "Software" actually REMOVED the field
    altogether from the EXIF data viewable by the freeware Irfanview.

    The question for me to figure out is whether removing the "Software" EXIF
    field would be indicative in certain cameras of tampering. Otherwise, I'll
    need to come up with a series of believable software values.

    BTW, what I was hoping to find was a freeware tool to spit EXIF data to a
    text (or comma separated value) file which could then be edited and read
    back in so that ALL EXIF fields of situational pertinence could be modified
    believably with a text editor without the tampering being readily apparent.
     
    EXIF Info, Jun 26, 2008
    #13
  14. EXIF Info

    EXIF Info Guest

    On Thu, 26 Jun 2008 15:25:04 +0200, CoMa wrote:

    >>The commandline program Jhead will do all this and more.

    > http://www.sentex.net/~mwandel/jhead/


    My bad for not explaining that jhead will only replace one EXIF data with
    another. AFAIK, jhead won't "fix" the thumbnail, nor will jhead set the
    EXIF data to match the photograph (e.g., pixel dimensions, subject
    distance, ownership information, etc.).

    As stated in the first post, I do use jhead to get a starting point for the
    believably falsified EXIF data, deliberately choosing out of scores of EXIF
    templates the closest match as a starting point.

    It would be nice if there was a freeware program that read in EXIF data
    from a TEXT file so that each field could be edited with a text editor and
    then jheaded over to the scented digital photograph.
     
    EXIF Info, Jun 26, 2008
    #14
  15. EXIF Info

    EXIF Info Guest

    On Wed, 25 Jun 2008 23:31:38 -0500, VanguardLH wrote:

    > I'm not familiar with EXIF metadata. You make it sound like there is a
    > history of changes to records within the EXIF metadata.


    One new item for the exif-editing checklist this brings up is the potential
    for unintentional "watermarking" in the EXIF data. That would be bad.

    To prevent unintentional watermarking, I would have to be sure to make the
    falsified EXIF data universal enough that a simple search engine didn't
    flag my particular photos any more than others in a programatic EXIF search
    such as that which Flickr and other public photo sharing sites routinely
    perform.

    Thanks for one more item for the checklist!
     
    EXIF Info, Jun 26, 2008
    #15
  16. EXIF Info

    Tom Yost Guest

    On Thu, 26 Jun 2008 06:48:36 -0700, EXIF Info <>
    wrote:

    >On Thu, 26 Jun 2008 10:45:48 +0100, hummingbird wrote:
    >
    >>>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.

    >
    >The reason is to create a believable yet false EXIF trail instead of no
    >EXIF whatsoever.
    >
    >That is, the viewer, perhaps thousands of them for any one photograph,
    >needs to believe the photograph was taken at the time and place with the
    >camera, setting, and lighting conditions that are in the EXIF fields.


    Sounds rather dodgy to me.
     
    Tom Yost, Jun 26, 2008
    #16
  17. EXIF Info

    EXIF Info Guest

    On Thu, 26 Jun 2008 04:05:21 -0700, John Corliss wrote:

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


    Interesting that freeware PhotoMe EXIF metadata editing program.

    PhotoMe runs a process called "Geonames.exe" which is apparently a
    geolocate feature which may be useful if we can point to a spot on Google
    Earth and have a program automatically insert EXIF metadata corresponding
    to the corresponding GPS coordinates.
     
    EXIF Info, Jun 26, 2008
    #17
  18. EXIF Info

    EXIF Info Guest

    On Thu, 26 Jun 2008 07:10:05 -0700, Tom Yost wrote:

    >>That is, the viewer, perhaps thousands of them for any one photograph,
    >>needs to believe the photograph was taken at the time and place with the
    >>camera, setting, and lighting conditions that are in the EXIF fields.

    >
    > Sounds rather dodgy to me.


    Practical applications
    - Privacy (hide situational information from industrial search engines)
    - Personals (make yourself younger and wider traveled)
    - Watermarking (create intentionally unique EXIF codes for search engines)
    etc.

    Oh, and the Loch Ness monster Area 54 style believable jokes too!
     
    EXIF Info, Jun 26, 2008
    #18
  19. EXIF Info

    EXIF Info Guest

    On Thu, 26 Jun 2008 09:13:27 -0500, lid wrote:

    >> BTW, what I was hoping to find was a freeware tool to spit EXIF data to a
    >> text (or comma separated value) file which could then be edited and read
    >> back in so that ALL EXIF fields of situational pertinence could be modified

    >
    > You can also edit the file with a binary editor, such as Hexedit.


    Very interesting. Will try.

    I wonder what happens when I accidentally insert bogus (i.e., invalid)
    information into the EXIF field with the binary editor ..............

    Should be interesting to test...... especially if a text-import tool
    doesn't yet exist.
     
    EXIF Info, Jun 26, 2008
    #19
  20. EXIF Info

    Ofnuts Guest

    EXIF Info wrote:
    > On Thu, 26 Jun 2008 10:46:26 +0200, Ofnuts wrote:
    >
    >> Making fake data is harder, some points to consider:

    > Exactly the point! The false EXIF data needs to roughly match the
    > photograph! But how?
    >
    >> - date/time/position:
    >> - lighting and sun position

    > Good point to check the shadows for outdoor shots to see if they match with
    > the time the picture was falsly taken. I'll add this to my checklist.
    >
    >> - an expert eye will have a rough idea of the focal length used.
    >> - if you have the subject distance in the Exif, it will be harder.

    > Yes indeed! This is the type of observation I was looking for.
    > I try to change the EXIF subject distance to match the photograph but I
    > didn't think about the focal length having to match. Are you sure an expert
    > could guess the focal length from a photograph?


    I'm far from an expert and I can usually tell if the picture was taken
    with a 35 or 50mm lens (35mm equiv. of course). How goof experts really
    are is your guess.

    >> - 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)

    >
    > Sensor size? Hmmmmmm.... From any given photograph, how would "sensor size"
    > be obvious to a trained observer? I don't know how to fake sensor size.
    > What would be rough estimation points for the falsified EXIF?


    Because the sensor size has a great influence on the DOF. A small sensor
    at 2.8 (P&S, bridge) has the same DOF as an APS/C sensor several f-stops
    higher (how much is "several" is a matter of actual sensor size, but
    IIRC on the 4/3 sensor (which is not that much smaller than an APS/C)
    you already have to open 2 f-stops more to achieve the same DOF).


    --
    Bertrand
     
    Ofnuts, Jun 26, 2008
    #20
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