One-time is good, Two-time is bad Let's break two-time pad
Let’s break two-time pad!
Contents
Intro
Below is the problem sets about this attack. Stanford and Maryland
Here is the solutionStanford then Maryland
Main points
if the same key used twice, then the result of (c1 Xor c2) will reveal a lot information about the original messages.
For example, the space is very crucial. ‘ ‘ ^ ‘a’ = ‘A’ and ‘ ‘ ^ ‘A’ = ‘a’. When ‘ ‘ Xor with a letter then it will produce corresponding letter. So it is the very start to break two-time pad.
Attack
Once we know the drawbacks behind it, we could easily break it.
Everything is covered in my code above.
If you are a Chinese, you could read detail
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