Problem 1
The following plaintext MAJORCONTRIBUTIONWASTHEUSEOFMATH was encrypted by Hill Cipher with 2X2 key matrix and the correspondent ciphertext is KWHGLIDRQVRPFRECPQEGIJCOAEHXKWI. Find a key matrix.
Problem 2
The ciphertext is VFCKOLQOBPTEJENAFJCHBEXS
Part of plaintext is lessplastic
Find Matirx Key and decrypt the message.
Problem 3
The ciphertext is KGYXSH
Part of plaintext is MASTER
Find Matirx Key, IF POSSIBLE. EXPLAIN!
Problem 4
Give an example of the plaintext/ciphertext pair for which it is impossible to find the key.