Question 1

Bod knows the 3 by 3 secret matrix and encrypted message. Then Bob is able to get encrypted message by multiplying inversed matrix by encrypted message.

Question 2

No. Eve has to find inverse of the secret matrix to decrypt the message.

Question 3

The secret matrix is $ \begin{matrix} - \frac{2}{3} & 0 & \frac{2}{3} \\ 0 & 1 & 0 \\ 4 &0 & -1 \end{matrix} $.


So, $ \begin{matrix} - \frac{2}{3} & 0 & \frac{2}{3} \\ 0 & 1 & 0 \\ 4 &0 & -1 \end{matrix} * \begin{matrix} - x \\ y \\ z \end{matrix} = \begin{matrix} - 2 \\ 23 \\ 2 \end{matrix} $.


Then, $ \begin{matrix} - x \\ y \\ z \end{matrix} = \begin{matrix} - 2 \\ 23 \\ 5 \end{matrix} $.

As a text, it is BWE.

Alumni Liaison

Ph.D. 2007, working on developing cool imaging technologies for digital cameras, camera phones, and video surveillance cameras.

Buyue Zhang