cryptography basics part iii

CRYPTOGRAPHIC BASICS PART III

---

In previous article we learnt about classification of cipher codes and then detailed analysis of two types of block ciphers maonosubstituted block cipher and polysubstituted block cipher.
The one not following my cryptography posts reading for first time must took a glance at older posts by the link given below
cryptographic-basics-part-i
cryptography basics part ii
today we will look to another type of block cipher known as transposition cipher,
Transposition cipher:It follows method of encryption by which position of simple text are shifted according to a regular pattern to form cipher text.
We will discuss three types of transposition ciphers here

• route cipher:let us take the example "WELCOME TO FREE LEARN HACKING"
  
  1. write the text in the blocks of length 5 "WELCO METOF REELE ARNHA CKING "
  2. now write in form according to the figure given below
     
  3. now the encrypted text becomes WMRAC KINGA EFOCL EEERN HLOTE
• columnar transposition:

we will use the same text "WELCOME TO FREE LEARN HACKING"

1. write the text in the blocks of length 5 "WELCO METOF REELE ARNHA CKING "
2. now write in form given below
   1 3 5 2 4
   W M R A C
   E E E R K
   L T E N I
   C O L H N
   O F E A G
3. now we have to chose a key suppose we chose our key as "CRYPT" then we will mark it in ascending order C-1 P-2 R-3 T-4 Y-5 whichever occurs first in alphabets
4. now the encrypted text becomes WMRAC COLHN EEERK OFEAG LTENI

double columnar transposition:

here we will repeat the same task two times we will use the same text "WELCOME TO FREE LEARN HACKING"

1. write the text in the blocks of length 5 "WELCO METOF REELE ARNHA CKING "
2. now write in form given below
   1 3 5 2 4
   W M R A C
   E E E R K
   L T E N I
   C O L H N
   O F E A G
3. now we have to chose a key suppose we chose our key as "CRYPT" then we will mark it in ascending order C-1 P-2 R-3 T-4 Y-5 whichever occurs first in alphabets
4. now the new text becomes
   1 3 5 2 4
   W M R A C
   C O L H N
   E E E R K
   O F E A G
   L T E N I
5. Now we will again apply the key crypt in the same manner
6. our encrypted text become WCEOL AHRAN MOEFT CNKGI RLEEE

There are hundreds of types of transposition cipher available.you can also make your own transposition cipher but it should be logically correct.
Transposition ciphers prove to be better cipher than substitution cipher
In next article we will be getting knowledge of more different powerful techniques.