An Improved Encryption Scheme

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Why Is This Code Easy To Break?
In this encryption scheme, letters are input and
then encrypted in the following way Each letter
is assigned a numerical value. A is assigned a
value of 1, B is assigned a value of 2, C 3,
and so on for all the letters of the alphabet up
through Z 26. Each value is increased by 2. If
the increased value is greater than 26, the value
is divided by 26 and we use the remainder. This
is a process known as modular arithmetic in base
26. The values are mapped back into letters. So
a value of 3 would be mapped to the letter C.
Example The letters of the word ZAP are mapped
to the numbers 26,1,17. These values are each
increased by 2 to result in 2,3,19. The values
2,3,19 are then mapped back to the letters BCR.
What Is This Code Easy To Break?
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ANSWER The pattern is fairly easy to recognize!
For example, the word YAM is mapped to the values
Y25, A1, and M13. These values are increased
to 2,3,15 so YAM is encrypted as ACO If you
simply have two strips of paper containing the
alphabet repeated. You line up the bottom strip
so that the encoded word corresponds to a real
word. The number of places the bottom strip is
shifted reveals the coding strategy.
To improve this encryption scheme, we could
transpose all values as part of the scheme. So 1
becomes 26, 26 becomes 1, 2 becomes 25, 25
becomes 2, etc.
For More Info, See An Improved Encryption
Scheme