Think like a hacker I have a message M which consists of two

Think like a hacker. I have a message M which consists of two words. The two words have been put into a 3x3 matrix with a space in between the words. I have a coding matrix C that is also 3x3 and whose entries are integers between -10 and 10 (inclusive of the endpoints). The \"coded\" message C*M is given below.

What is the message M? (In English, not in numbers)

Solution

I don\'t understand what exactly do you mean by \"(In English, not in numbers)\" because this is a questio n of Cryptography which uses mathematics. So without mathematics it can\'t be explained. Sorry for that !

Now from a mathematical point of view it is an established theorem that :

if,

A * B = C

then,

A = B^-1 * C

where A,B,C are matrices and B^-1 is the inverse matrix of the matrix B.

now from a cryptographic point of view we know that :

C * M = Coded matrix

so to get M matrix just find the inverse of C matrix that is C^-1 and do matrix multiplication with coded matrix.

so,

M = C^-1 * (C*M)

and you get the message.