InCTF Jr Qualifiers 2021
Starts 6PM, 28th Dec
InCTF Jr

Renege

Medium Cryptography

Author: Chandu Kona

  • As the key length is 6 and the key is used to encrypt inctfj to fvddla we need to pick the first 6 bytes i.e inctfj for generating the key
  • From this we get the key as crypti and as we need to decrypt this vigenere
  • the lookup matrix above was slightly inverted when compared to the original vigener matrix

Exploit

key : crypti