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 Save encryption meta information in PNG file?
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PeterPanino

982 Posts

Posted - Dec 18 2022 :  04:13:13  Show Profile  Reply
I encrypt an image using this code:

ImageEnView1.Proc.Encrypt(Edit1.Text, ieeaTEA2);


The Documentation says: "There is no way to know whether an image is encrypted unless you insert special tags"

UPDATE: Unfortunately, the XMP metadata fields don't seem to be editable in the TIEMetaListView control, although the XMP Specification https://archimedespalimpsest.net/Documents/External/XMP/XMPSpecificationPart3.pdf states about PNG files: "An XMP packet is embedded in a PNG graphic file by adding a chunk of type iTXt."

UPDATE2: Is there a reason why TIEMetaListView does not handle the file-type-specific meta-data? Example:
PNG_TextKeys, PNG_TextValues, etc.
GIF_Comments, etc.
etc.

UPDATE3: I have now started to tag the image when encrypting it with this code:
ImageEnView1.IO.Params.PNG_TextKeys.Add('IEEncryption');
ImageEnView1.IO.Params.PNG_TextValues.Add('True');

In this way, when I reload the encrypted PNG file, I can automatically show the Encryption/Decryption Panel to allow the user to decrypt the image.

xequte

39053 Posts

Posted - Dec 18 2022 :  15:50:33  Show Profile  Reply
Hi Peter

Yes, PNG_TextKeys is a good option for PNG files.


Nigel
Xequte Software
www.imageen.com
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PeterPanino

982 Posts

Posted - Dec 18 2022 :  23:30:24  Show Profile  Reply
Can you provide an example to show (and edit) PNG and GIF metadata in a TIEMetaListView?
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xequte

39053 Posts

Posted - Dec 19 2022 :  00:24:12  Show Profile  Reply
Hi Peter

Sorry PNG text keys and GIF comments are not include in TIEMetaListView at this time. I have almost never seen these fields used in the wild. Is there a reason you want to support them?

Nigel
Xequte Software
www.imageen.com
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PeterPanino

982 Posts

Posted - Dec 19 2022 :  04:25:30  Show Profile  Reply
Hi Nigel

What other way is to support metadata in PNG and GIF files?

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xequte

39053 Posts

Posted - Dec 19 2022 :  15:20:50  Show Profile  Reply
Hi

What exactly are you wanting to do? Provide a way for your users to add text comments to their images (for viewing/editing in your application only)?



Nigel
Xequte Software
www.imageen.com
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