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Posts Tagged ‘day 5’

HACKvent 2015: Day 5

08 Dec 2015
CTF: Hackvent 2015
Link to challenge: http://hackvent.hacking-lab.com
Date Completed: 08 December 2015

Challenge

You are given the following file:
Download PDF File

Solution

So we open the PDF file to find 1 QR image in a ball. We scan it and we get the text Oooops ! .

We then use an online tool to extract all images from the PDF (link). I do this because PDF files store all image files, even if they are completely overlapped by other images.

We then find 3 different images:
PDF Image 1 PDF Image 2 PDF Image 3

As it turns out, the QR image square was overlapping the other QR image in the ball. So we simply scan the QR image in the ball and get the flag.

Flag:  HV15-bkPb-tPEM-Fh3n-wvOi-5ZgD

 
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Advent Of Code: Day 6

06 Dec 2015
CTF: Advent Of Code
Link to challenge: http://adventofcode.com
Date Completed: 06 December 2015

The Challenge

Solution

I split up the solutions for part 1 and part 2. Was almost tempted to go for a numpy and scipy sparse matrix solution but a 1000×1000 matrix is small enough for a dense matrix.

Part 1

 

Part 2

 

 
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Advent Of Code: Day 5

05 Dec 2015
CTF: Advent Of Code
Link to challenge: http://adventofcode.com
Date Completed: 05 December 2015

The Challenge

Solution

Another quick and simple Python solution!

 

 
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Posted in Advent Of Code