Two French researchers — Michel Sassano and Clement Storck — have reconstructed a blurred QR code to gain access to a Bitcoin wallet that was holding $1,000.
The money was put there by Bitcoin entrepreneur Roger Ver during a TV interview on the Bitcoin cryptocurrency with French TV station France 2. The TV interview aired on October 15 and is available on YouTube, here.
On a TV screen, Ver published the wallet's private access key and a QR code. Ver said the first person who accesses the account afterthe TV interview first airs can transfer and keep the money.
At the time, Ver didn't know that French laws prevented the TV station from showing the account's private key and QR code. France 2 was not authorized to give out money prizes during that particular TV transmission, so it blurred out both details.
The broadcast started a frenzy among French hackers and Bitcoin aficionados, who began looking for ways to gain access to the account and claim the prize.
The winners were Sassano and Storck, who claimed the prize on 17, two days later. The two said they spend 16 hours reverse-engineering the blurred image and trying to piece together blurred dots in correlation with the QR code's standard format.
They got lucky because, towards the end of the transmission, France 2 technicians failed to properly blur out a part of the private key, revealing some of the characters.
The entire process is detailed in a lengthy, but very interesting, blog post. We could never do it justice if we would summarize the process, so if you have ten minutes, give it a read.
The hidden message coming from their hack is that blurred QR codes or barcodes are not safe anymore.
Users who share such data online should use full blocks of color when editing images for sensitive details.