Description

As the owner of a computer forensics company, you have just been given the following note by a new client:

I, Albert Charles Montgomery, have just discovered the most amazing cypher for encrypting messages. Let me tell you about it.

To begin, you will need to decide on a set of symbols, call it S, perhaps with the letters RATE. The size of this set must be a power of 2 and the order of the symbols in S is important. You must note that R is at position 0, A at 1, T at 2, and E at 3. You will also need one permutation P of all those symbols, say TEAR. Finally you will need an integer, call it x. Together, these make up the key. Given a key, you are now ready to convert a plaintext message M of length n (M[0], M[1]... M[n-1]), that has some but not necessarily all of the symbols in S, into a cyphertext string C, also of length n (C[0], C[1],...C[n-1]), that has some but not necessarily all of the symbols in S.

The encrypting algorithm computes C as follows:

Calculate an integer d as the remainder after dividing the integer part of (n^1.5 + x) by n. This can be expressed more succinctly as d = (int)(n^1.5 + x) % n, where \\\

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