Google CTF 2019 (Quals) – Quantum Key Distribution

This years online qualification for the Google Capture The Flag finals (ctftime.org) ran from 22/06/2019, 00:01 UTC to 23/06/2019 23:59 UTC.

As last year, there were plenty of diversified challenges, which were worked out very well.

I tried to take at least a look at as much challenges as possible and solved the challenge Quantum Key Distribution, which was relatively easy based on the amounts of solves. Within this article I want to share my writeup on this challenge.

The writeup is divided into the following sections:

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VolgaCTF 2019 Qualifier – Blind

The VolgaCTF 2019 Qualifier (ctftime.org) took place from 29/03/2019, 15:00 UTC to 31/03/2019 15:00 UTC.

There has been a really interesting RSA crypto challenge called Blind, which I would like to share with you in this writeup.

The article is divided into the following sections:

Challenge description
What does the script do?
Blind RSA Signature
Retrieving the Flag

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HACKvent18 writeup

For the sixth time in a row now hacking-lab.com carried out the annual HACKvent. Each day from the 1st of december until the 24th a new challenge is published. I would have loved to spend more time on it, but time is a rare resource especially on the days before christmas 😉 After all I managed to solve 21 of 24 tasks:

Easy
Day 01: Just Another Bar Code
Day 02: Me
Day 03: Catch me
Day 04: pirating like in the 90ies
Day 05: OSINT 1
Day 06: Mondrian
Day 07: flappy.pl
Medium
Day 08: Advent Snail
Day 09: fake xmass balls
Day 10: >_ Run, Node, Run
Day 11: Crypt-o-Math 3.0
Day 12: SmartWishList
Day 13: flappy’s revenge
Day 14: power in the shell
Hard
Day 15: Watch Me
Day 16: Pay 100 Bitcoins
Day 17: Faster KEy Exchange
Day 18: Be Evil
Day 19: PromoCode
Day 20: I want to play a game
Day 21: muffinCTF (Day 1)
Day 22: muffinCTF (Day 2)
Day 23: muffinCTF (Day 3)
Final
Day 24: Take the red pill, take the blue pill

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