On my exam, we had to solve this problem:
message matrix is:
[20, 19, 14; 17, 0 10]
and the ciphertext matrix is:[18, 15, 16; 3, 24, 24].
Find key matrix.
I couldn't solve this problem, because I tried to find key matrix by multiplying
[20, 19, 14; 17, 0 10]^-1 and [18, 15, 16; 3, 24, 24], but I wasn't able to calculate [20, 19, 14; 17, 0 10]^-1, because it's not a square matrix.
How can I decode a Hill Cipher without a key?
