DECIME - Editorial

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PROBLEM LINK:

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Author, Tester, Editorialist: Vaibhav Gupta

PROBLEM

Convert the given cipher text to plain text.

QUICK EXPLANATION

Given [monoalphabetic substitution cipher][1], use the frequency analysis to identify the substitutions and use the mappings to find the plain text.

EXPLANATION

  1. Check the character with the largest frequency in the cipher text, mark it as ‘e’.

  2. The most common double letters in order of frequency

       	<center>SS, EE, TT, FF, LL, MM, OO </center>

  3. The most common trigraphs in order of frequency

       	<center>THE, AND, THA, ENT, ION, TIO, FOR, NDE, HAS, NCE, TIS, OFT, MEN</center>

  4. More about frequencies can be found out [here][2].

ACCEPTED SOLUTION:

ciphersecurity’s Solution
[1]: Substitution cipher - Wikipedia
[2]: http://scottbryce.com/cryptograms/stats.htm