Line 11: Line 11:
  
 
== Part C.3 ==
 
== Part C.3 ==
 +
 +
<pre>
 +
%{
 +
  Jeremiah Wise
 +
  Homework #3 Part C.3
 +
%}
 +
 +
message = [1 0 4; 0 1 0; 1 0 1];
 +
 +
encryptedVector = [2 0 0; 0 1 0; 0 0 3];
 +
 +
secretMatrix = ((inv(message)) * encryptedVector).'
 +
</pre>

Revision as of 13:31, 19 September 2008

Application of Linearity

Part C.1

If Bob knows the secret matrix used to encrypt the message, He can simply take the inverse of that matrix and multiply the encrypted vector by the inverted matrix.

Part C.2

Yes she can just solve the system of equations represented by the matrix, but in general it is easier to just use matrices to solve such equations.


Part C.3

%{
  Jeremiah Wise
  Homework #3 Part C.3
%}

message = [1 0 4; 0 1 0; 1 0 1];

encryptedVector = [2 0 0; 0 1 0; 0 0 3];

secretMatrix = ((inv(message)) * encryptedVector).'

Alumni Liaison

Prof. Math. Ohio State and Associate Dean
Outstanding Alumnus Purdue Math 2008

Jeff McNeal