Invisible digital watermark

[Sveinn í Felli]

Maybe something similar to image steganography could be used?
That is a process where one can embed encrypted message/image into a 
picture. Pixelknot is such an OSS-application for Android, see 
<https://guardianproject.info/apps/pixelknot/>

Simon, do you know how well the Fourier markings survive through 
modifications by image sharing services?

Regards,
Sveinn í Felli

Þann fös 12.maí 2017 12:38, skrifaði Louis A. Turk:
> On 05/12/2017 07:05 PM, Gilles Caulier wrote:
>> Very interesting. Please comment this entry in bugzilla accordingly :
>>
>> https://bugs.kde.org/show_bug.cgi?id=268981
>>
>> Thanks in advance
>>
>> Gilles Caulier
>>
>> 2017-05-12 12:03 GMT+02:00 Simon Frei <freisim93 at gmail.com>:
>>> There is a G'MIC filter that embeds text in the fourier domain, it is
>>> called "Fourier watermark" (and "Fourier analysis" to retrieve the
>>> info): https://gmicol.greyc.fr/
>>>
>>> On 12/05/17 11:35, Gilles Caulier wrote:
>>>> You cannot. Invisble watermark use wavelets encoding methods which are
>>>> patented in US and impossible as i know to code in open source...
>>>>
>>>> Best
>>>>
>>>> Gilles Caulier
>>>>
>>>> 2017-05-12 10:42 GMT+02:00 Louis A. Turk <louisaturk at firmanelohim.org>:
>>>>> How can I do invisible digital watermarking with digikam5 as mentioned
>>>>> here:
>>>>> https://docs.kde.org/trunk5/en/extragear-graphics/digikam/using-dam.html#using-dam-copyright
>>>>>
>>>>> How can I do a regular watermark?
>>>>>
>>>>> drl
>>>
>>>
>
> Thank you Gilles and Simon. Hopefully, the impossible may be possible
> after all.
>
> drl
>