# Anarchists corrupted my barcode!

Somebody corrupted my QR Code.

Can you tell me who did this and when it happened?

Hint:

• Welcome to Puzzling! To clarify, this is a puzzle you created yourself, right? Dec 6, 2020 at 18:33
• @bobble yes it is. It has a single solution in a few steps. Dec 6, 2020 at 18:36

My guess: Gabriel Syme corrupted your QR Code on Thursday.

Taking Sleafars work on the DataMatrix, we get the first hint: G SYME

I play around some time with the QR Code, trying various approaches (e.g: subtracting the DataMatrix from the QR Code).
Eventually I managed to decode the corrupted QR Code to the following Strings: "The Man W} W~nThuúªay", "The Man Wh7 Wlq ThtÌÌÌay".
-> The Man ??????? Thursday

Some search on the internet led to the novel "The Man Who Was Thursday" by G. K. Chesterton where the main character is an undercover detective called Gabriel Syme

• Well done! The Anarchists part of the title could have saved you some time via searching, but nevertheless I'm impressed you made the effort to decode the corrupted part and how well it worked as a clue. Dec 7, 2020 at 23:41

If we look at the link provided by the OP, we can see examples for 2 different barcode types: GS1 DataMatrix and GS1 QR Code.

The barcode in the puzzle looks like a QR code ("concentric" squares in 3 corners), but it can't be decoded. However, if we look more closely, we can see a DataMatrix code in the centre (2 black borders, 2 borders with alternating black/white dots):

This one can be decoded to the string G SYME.

My best guess is, that G. Syme corrupted the barcode in 1949 (based in the info in the link).

Note: There are more areas in the bottom which look like they could work as DataMatrix codes, but I wasn't able to decode them.

• You're very close. Dec 7, 2020 at 18:37
• I used my employer's barcode app on my phone. It read the QR code as 4539 after some tweaking. Otherwise, it agrees with the decoding you have in your answer. Dec 7, 2020 at 18:38
• @flinty I assume this means, that the time is wrong? Dec 7, 2020 at 18:39
• @Sleafar yes and the person (not the name) is wrong. But you've taken the right steps so far. Dec 7, 2020 at 18:41
• OK, I also got a 1583 out of it, mostly by rotating. This makes me think it is unintended. Dec 7, 2020 at 18:49