Jin Lei is from Oufei Temple
Qubits | Official account QbitAI
Tell a horror story.
In the morning, I chatted with my colleagues on WeChat and talked about the recent changes of a female colleague.
As a result, he backhanded the text with a mosaic and threw the screenshot into the group:
I still owe a knife to make up for it:
@XXX, he said you have bad words
Unexpectedly, this colleague came over with great momentum and directly pointed out the content of the "secret text".
At the time, I was like this:
Seeing this, the teacher added:
What age do you think I won't recognize when I play mosaic? Restore in minutes Okay!
……
Curious as I was, I immediately launched an "investigation" of this technology.
(PS: The original picture of the chat was revealed at the end of the article)
How to restore text with mosaics?
Not to mention, Dan Petro (hereinafter referred to as Dan), the chief researcher of a foreign company, published such a post in the past two days.
He directly pointed out the main points:
Hitting mosaics (pixelation) is a very bad, insecure, and method that can leak sensitive data.
To test his claims, Dan wrote a tool called Unrealacter himself.
Then the live demonstration of how this tool restores the mosaic text little by little:
From the above example, it is not difficult to see that even if the original text is a thick layer of mosaic, it is still like "running naked" in front of this tool.
Maybe you will say that this thing will be complicated to operate?
No, no, no.
It's very simple, just 2 steps:
Install dependencies with npm install
Start with npm start
There are also pictures of restored mosaics
But a very real problem is that the text restored by Depix is not very good from the visual effect:
The text restored by Depix is still mushy in some places.
Therefore, a researcher at the foreign Jumpsec Lab pointed out this problem and also attached a more interesting challenge:
If you have cracked your password, please contact us.
This challenge became intriguing to Dan, which is why he developed Unrealacter.
So, with the blessing of Unrealacter, Dan successfully broke through this challenge:
Dan then contacted the researcher, and in the email response, he also confirmed that Dan's results were correct:
Not only that, Dan also said that mosaics like those played with smudges, whether in GiMP, Photoshop or other editors, the results are the same.
Therefore, his cracking method should have a certain versatility.
Of course, in life we will more or less have the need to "code", since mosaic is not safe, is there a better way?
Dan's response to this is:
Cover with black bars.
In fact, the matter of "restoring mosaics" has long been studied by the AI community.
For example, Duke University's USE is one of them, which also topped the CVPR.
But what it fixes is not the text, but the portrait, for example:
From a principle point of view, it is essentially a generative adversarial network (GAN).
PLUSE is mainly based on blurry mosaic pixels, "painting" a new non-existent face, and then compressing back to the mosaic state compared with the original picture, and taking out similar versions to show.
Of course, this technology is not perfect, and there are times when the car rolls over.
For example, netizens tried Mario, and the result...
Emmm...... This "taste" is not ordinary.
One More Thing
Finally, let's reveal the answer to the opening story.
It's a bitter lesson...
Project Address:
https://github.com/bishopfox/unredacter
Reference Links:
[1]https://bishopfox.com/blog/unredacter-tool-never-pixelation
[2]https://labs.jumpsec.com/can-depix-deobfuscate-your-data/
[3]https://arxiv.org/abs/2003.03808