Homeland Security says that one of our messages to a client and one from the same client are suspected of being secret

communications with a terrorist. The challenge is that the messages are encrypted and we only have a few clues from

Whosethis Guy$$s notes. Key notes include:

$1.$A equals $1,$ B equals $2,$ C equals $3,$ D equals $4,$ etc.$.$

$2....$matrix size four rows by$...$

$3.$ multiply with encrypter to encrypt, inverse to decrypt$.$

$4.1,2,3,2,$ space, $2,5,6,4,$ space, $1,1,4,4,$ space, $2,4,6,5$

Ima Snoop, Mr Guy$$s officemate says she thinks this was used as his encrypter. We believe that the word space was

used to indicate a new row in the encryption matrix.

There are two messages of interest to Homeland Security.

A$.$ The first is an array of numbers that we received from the client:

B$.$ The second message is regularly worded and is from our firm to the client, $$Beware of gas crisis.$$

Can you help us decipher these messages? Specifically, here$$s what I$$m asking you to do$.$

$1.$ Decipher the message that we received from the client $[$Message A above$].($Assume that a value of $0$ represents a blank

space in this decryption.$)$

$2.$ Encrypt the message that we sent to the client. $[$Message B above$]$ using the same rules where $0$ represents a blank

space between or after words. We are hoping that we could find the same encrypted message on the client$$s computer

to prove that we are innocent.