This looks like an ordinary, boring image — but it really isn't.
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It used to be ordinary.
But after a brief encoding process, it became a remarkably effective way to transmit information securely.
The technique is called steganography, and it refers to concealing information within an item in such a way that only someone who knows it's there can find it.
To perform the encoding, I used an open-source application called OpenStego.
In the software, I selected the file I wanted to encode, the image file I wanted to encode it into, and the name of the output file.
A few seconds later, I had an image file that looks completely identical to the original — but anyone who receives it can enter the password into the same application and extract the hidden file.
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Concealing information this way is extraordinarily effective, because even someone looking directly at the image would never suspect it's hiding anything extra.
It can be used by legitimate parties for secure communication, but of course it can just as easily be exploited by those trying to evade the law.
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One drawback of encoding data inside an image is the significant change in file size, which hints that something is being concealed.
If the original file was under a megabyte, the encoded file was already 30 MB — far beyond what you'd expect for a standard image file.
However, the technique works equally well with audio and video files, and since video files are inherently large, the added bulk of the encoded content is unlikely to raise any eyebrows.
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History offers fascinating examples of steganography in practice, such as transmitting information through invisible ink or stitching in a specific color along a garment's lapel.
The digital version of the technique is simply one more example of the remarkable creativity of the human mind in devising encrypted communication.