chalkboard

• grep -v “I WILL NOT BE SNEAKY”
• Inbvert matching, finds lines that do not have this full content
• We can assemble the flag from that
• picoCTF{chalkboard_bert_7c69b78b}

Cryptography

RSA

• For n, n is made up of p*q where p and q are supposedly large primes
• notice the even number for n… only even prime is 2 (any other prime is odd, and odd*odd = odd).
• that manes p*q = N, one of pq must be 2
• you can get decryption key this way
• Code decryption in python

GUess my Chesse part 1

• affine cihper
• each iteration of NC gives different a b values for afffine cipher
• encrypt 2 cheeses, check for which a b value with auto bruteforcer on dcode
• decrypt message with a b