Why Blurring or Mosaicing Important Information is a BAD Idea

Outsmart Malicious Hackers


I saw a pretty interesting article a few days attempting to reverse engineer the mosaic tool used often online to obscure sensitive or confidential information.

The article shows that the mosaic isn’t actually very random, and in a way you can brute force reverse engineer the mosaic to reveal the contents before they were obscured.

It’s ok for faces, but when it comes to letters/numbers and text it can be uncovered.

For the most part this is all fine with peoples’ faces as there isn’t a convenient way to reverse the blur back into a photo so detailed that you can recognise the photo. So that’s good if that is what you intended. However, many people also resort to blurring sensitive numbers and text. I’ll illustrate why that is a BAD idea.

Suppose someone posted a photo of their check or credit card online for whatever awful reason (proving to Digg that I earned a million dollars, showing something funny about a check, comparing the size of something to a credit card, etc.), blurring out the image with the far-too-common mosaic effect to hide the numbers.

Which is true, it is very common.

There is some ubermath geek stuff after this, analysing the brightness vector of the mosaic areas.

In this case, the account number 0000001 creates mozaic brightness vector a(0000001)=[213,201,190,…]. We find the mozaic brightness vector for every account number in a similar fashing using a script to blur each image and read off the brightnesses. Let a(x) be the function of the account number x. a(x)_i denotes the ith vector value of the mozaic brightness vector a obtained from account number x. Above, a(0000001)_1 = 213.

We now do the same for the original check image we found online or wherever, obtaining a vector we hereby call z=[z_1,z_2,…z_n]:

Anyway go ahead and check the article out, a very interesting read and a real example of proper hacking, thinking of a solution to something, thinking how to break something..

You can read more in the full article here:

Why blurring sensitive information is a bad idea

Posted in: Hacking News, Privacy

,


Latest Posts:


snallygaster - Scan For Secret Files On HTTP Servers snallygaster – Scan For Secret Files On HTTP Servers
snallygaster is a Python-based tool that can help you to scan for secret files on HTTP servers, files that are accessible that shouldn't be public and can pose a s
Portspoof - Spoof All Ports Open & Emulate Valid Services Portspoof – Spoof All Ports Open & Emulate Valid Services
The primary goal of the Portspoof program is to enhance your system security through a set of new camouflage techniques which spoof all ports open and also emulate valid services on every port.
Cambridge Analytica Facebook Data Scandal Cambridge Analytica Facebook Data Scandal
One of the biggest stories of the year so far has been the scandal surrounding Cambridge Analytica that came out after a Channel 4 expose that demonstrated the depths they are willing to go to profile voters, manipulate elections and much more.
GetAltName - Discover Sub-Domains From SSL Certificates GetAltName – Discover Sub-Domains From SSL Certificates
GetAltName it's a little script to discover sub-domains that can extract Subject Alt Names for SSL Certificates directly from HTTPS websites which can provide you with DNS names or virtual servers.
Memcrashed - Memcached DDoS Exploit Tool Memcrashed – Memcached DDoS Exploit Tool
Memcrashed is a Memcached DDoS exploit tool written in Python that allows you to send forged UDP packets to a list of Memcached servers obtained from Shodan.
QualysGuard - Vulnerability Management Tool QualysGuard – Vulnerability Management Tool
QualysGuard is a web-based vulnerability management tool provided by Qualys, Inc, which was the first company to deliver vulnerability management services as a SaaS-based web-service.


Comments are closed.