6. A cryptanalyst has determined that the three most common trigraphs (blocks of length three) in a ciphertext are, LME, WRI and ZYC and guesses that these ciphertext trigraphs correspond to the three most common trigraphs in English text, THE, AND, and THA. If the plaintext was enciphered using a Hill trigraphic cipher described by , what are the entries of the enciphering matrix ?
Solution
6.
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