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substitution2

  • Description: It seems that another encrypted message has been intercepted. The encryptor seems to have learned their lesson though and now there isn't any punctuation! Can you still crack the cipher?
  • Difficulty: Medium

🔎 Solution​

Just like the two previous challenges (substitution0 and substitution1), using the same tool allows us to determine the substitution key as MJUANEDSCLOXGKHQVFTIBZWPRY.

The decrypted plaintext is rewritten in a clearer form below:

There exists several other well-established high school computer security competitions, including CyberPatriot and US Cyber Challenge. 
These competitions focus primarily on systems administration fundamentals, which are very useful and marketable skills. 
However, we believe the proper purpose of a high school computer security competition is not only to teach valuable skills, but also to get students interested in and excited about computer science.

Defensive competitions are often laborious affairs and come down to running checklists and executing config scripts. 
Offense, on the other hand, is heavily focused on exploration and improvisation, and often has elements of play. 
We believe a competition touching on the offensive elements of computer security is therefore a better vehicle for tech evangelism to students in American high schools.

Further, we believe that an understanding of offensive techniques is essential for mounting an effective defense, and that the tools and configuration focus encountered in defensive competitions does not lead students to "know their enemy" as effectively as teaching them to actively think like an attacker.

picoCTF is an offensively oriented high school computer security competition that seeks to generate interest in computer science among high schoolers, teaching them enough about computer security to pique their curiosity, motivating them to explore on their own, and enabling them to better defend their machines.

The flag is picoCTF{N6R4M_4N41Y515_15_73D10U5_702F03FC}.

🚩Flag​

picoCTF{N6R4M_4N41Y515_15_73D10U5_702F03FC}