A well-known concept from classical cryptanalysis is the Kasiski test. You have found an

old ciphertext, where you know that the plaintext discusses cryptographic methods. You suspect

that a Vigenere cipher has been used and therefore look for repeated strings in the ciphertext.

You find that the string TICRMQUIRTJR occurs twice in the ciphertext. The first occurrence

starts at character position 10 in the text and the second at character position 241 (we start

counting from 1). You make the inspired guess that this ciphertext sequence is the encryption of

the plaintext word cryptography. If this guess is correct, what is the key?