(New page: == How can Bob decrypt the message? == Since Alice specified that she was going to use 3-by-3 secret matrix and we have a decrypted matrix and its pre-decrypted matrix, we can solve for ...) |
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== How can Bob decrypt the message? == | == How can Bob decrypt the message? == | ||
Since Alice specified that she was going to use 3-by-3 secret matrix and we have a decrypted matrix and its pre-decrypted matrix, we can solve for secret matirx by multiplying encrypted matrix by inverse of decrypted matrix | Since Alice specified that she was going to use 3-by-3 secret matrix and we have a decrypted matrix and its pre-decrypted matrix, we can solve for secret matirx by multiplying encrypted matrix by inverse of decrypted matrix | ||
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| + | == Can Eve decrypt the message without finding the inverse of the secret matrix? == | ||
| + | Yes, she can set an equation that <math>decrypted*secret=encrypted</math> | ||
Revision as of 17:06, 19 September 2008
How can Bob decrypt the message?
Since Alice specified that she was going to use 3-by-3 secret matrix and we have a decrypted matrix and its pre-decrypted matrix, we can solve for secret matirx by multiplying encrypted matrix by inverse of decrypted matrix
format rat A=[1 0 4;0 1 0;1 0 1]; B=[2 0 0;0 1 0;0 0 3]; secret= B*inv(A) % secret = % % -2/3 0 8/3 % 0 1 0 % 1 0 -1 %
Can Eve decrypt the message without finding the inverse of the secret matrix?
Yes, she can set an equation that $ decrypted*secret=encrypted $
