This is the final part of a 3-part challenge regarding the classical transposition. You can solve this challenge with pen and paper or by writing a small computer program. In this challenge, the plaintext was first encrypted with a monoalphabetic substitution cipher. After that, the result was encrypted a second time with the irregular columnar transposition to create the final ciphertext. The used key length for the columnar tranposition has less than 10 characters.