DRDO CSE 2022 Paper 2 | Question: 27

Question

A transposition cipher (but not a rail-fence cipher) was used to produce the following ciphertext:

$\text{X 2! H M E S S S E 2 Y T A 2 I I A}$

The key used was: $5 \; 2 \; 6 \; 3 \; 4 \; 1.$

What was the plaintext used (in English)?

Answer 1

There are 18 letters and from the key we understand that there are 6 columns.so there are 3 rows and 6 columns

so by arranging the letters from key 5 2 6 3 4 1

As first 3 letters to 5^th column,next to 2^nd coln and vice versa.

key	1	2	3	4	5	6
	I	H	E	T	X	S
	I	M	2	A	2	S
	A	E	Y	2	!	S

 

now arranging the letters to form a sentence by seeing the first row.as IHETXS can be rearranged as THIS EX SO THE TABLE CHANGE TO

4	2	1	6	3	5
T	H	I	S	E	X
A	M	I	S	2	2
2	E	A	S	Y	!

 

THE ANSWER IS THIS EXAM IS 222 EASY!