I am not sure how to get the key for the following Monoalphabetic Cipher question. This is a textbook question and I know the answer, but I juts dont know how they got the key.
Decrypt the following Cipher texts, and give the key. (Note that the correct key is the Encryption key, so if F changes to H and F is the plaintext, then the key is “C”):
(a) YRRYAIYRMLAC (b) DOBXQPZELLI
Answer: a) Text:
ATTACKATONCE Key =
X b) Text:
GREATSCHOOL Key =
Can somone please explain to me how to determine the key?