hello everyone my name is vijay kumar devireddy and i am glad to have you back on my episode 04 well we had

discussed about cryptography and how it helps us to protect the information in the internet world in this 

episode we are going to discuss about how it had evolved . for that 

we will jump into the history to know it briefly .

Sending secret messages has been a documented human activity for thousands of years. The earliest example I 

am aware of can be found in the bible, from approximately 2600 years ago. it was named as The AT BASH cipher 

which we call it as substitution ciper now in this Encryption works by substituting each letter in the alphabet 

by another letter.

Caesar’s Cipher

Another substitution cipher from the ancient world is “Caesar’s Cipher”, named after Julius Caesar who used 

it in his private correspondence, about 500 years after ATBASH cipher. To encrypt a message with 

Caesar’s cipher, each letter is replaced by a letter 3 places earlier in the alphabet: “shifting back by 3” 

- so D becomes A, E becomes B, and wrapping around so A becomes X.

For many centuries cryptography was used quite extensively - as a “dark art”, employed by royals, diplomats, 

spies, and the military. It played an important role in many historical events. Probably the most famous in

 modern history is the story of the Enigma cipher used by the Germans in World War 2, and the allied forces’

 success in breaking that cipher.

 

This all changed in the 1970s. By then important and sensitive electronic communication systems emerged in the

 civilian market - most notably “Automatic Teller Machines” (ATMs) allowing cash withdrawals. Motivated by the 

need to protect civilian communications from criminals, the US standards body (which is now called NIST), 

realized that a cipher is needed to protect sensitive (but non-classified) information. 

The result was the design, and public standardization, of the first civilian cipher, called the Data Encryption

 Standard (DES). DES was designed by IBM in the 1970s and became a US federal standard in 1977.

and des was used for 30 years and later found it as vulnerable to protect the sensitive information with the 

modern technologies we will discuss this later