Hey guys! Here is a guide to Introduction to Cryptography: Part 2, How to encrypt secret messages like Enigma Machine.

## Reverse-Trail

We all understand language through our brain….but can we……

NIARB ROUHG UORHT EHAUG NALDN ATSRE DNUXQ

Yeah! I know that’s look really confusing. It’s not like that old simple one.(Do you suppose will an interceptor try to pronounce it!)

Now eliminate Q and X from the end as they are nulls and read right-to-left. Now can you read this!

QXUND ERSTA NDLAN GUAGE THROU GHOUR BRAIN

Now if we read then, we can

UNDERSTAND LANGUAGE THROUGH OUR BRAIN

A reverse trial code seems easy to break but you can fool anyone and be the smartest spy. Let’s take this a little further. What if we could use synonyms instead of real words! Give it a try.

Suppose you have to organize a secret-spy meeting but due to bad weather you have to change the time of the meeting. Now pass on this message secretly to your friends.

SLOW [ DELAY ] THE FLOW [ TIME ] OF THE MEET BY SIXTY MINUTES [ 1 HOUR ] !

Now do the reverse trial and 5 letter grouping.

SETUN IMYTX ISYBT EEMEH TFOWO LFEHT WOLSQ

( Q is used as null to complete 5 letter group)

Seems pretty complicated!! Let’s try another one.

Imagine you are in battlefield and you just see that the enemy jet has just take off from it’s base towards you nation. Now you have to pass on this message to your Commander!

ENEMY BIRD [ JET ] FLEW [ COMING ] TO OUR PLANET [ NATION ]. STAY ALERT!

Let’s try encrypting this message.

ZTREL AYATS TENAL PRUOO TWELF DRIBY MENEQ

(Using Z and Q as the nulls both at the starting and at the end~!)

As soon as you break the encoded “reverse trail” messages that follow, create some of your own to send to your fellow cryptographers.

## Homework-for-you

Here’s another encrypted message for you have to you decrypt.

PLsni arbeh thtiw yugeh ts’tin ugeht htiws yugeh twons ‘tiwon seore hylek ilnue romto laeva heWow

Hint : Alan Turing in The Imitation Game (2014)

Comment the decoded message!!

Part 3 of this interesting cryptography for beginners’ guide will soon be posted on MathCompt. Stay tuned!