CRYPTOGRAPHY

 

Cryptography: A brief history

 

 

 

 

In the current scenario of computer usage that predict is that network are likely to be present everywhere, security has become much talked about issue. Especially with the relatively easy access to the internet the confidence in the sanctity of the data is a major concern.

 

However the science of cryptology is at least 4,000 years old. Cryptology is defined as the design and analysis of codes and cipher’s. In the first 3,000 years, cryptology was developed independently in several ancient cultures including Egypt India and Mesopotamia. Perhaps the oldest evidence of cryptology is an ancient inscription, carved about 1900 BC in the main chamber of an Egyptian tomb. It used some unusual hieroglyphic symbols in place of more ordinary symbols.

 

Plain:               ABCDEFGHIJKLMNOPQRSTUVWXYZ

 

Cipher:            DEFGHIJKLMNOPQRSTUVWXYZABC

 

Using this system the secret message “ZHOFRPH WR WKH FRPSXWHU FRXUVH” would actually mean “welcome to the computer course”. There were of course other systems developed around the similar time in the history which includes approach such as:

 

·        Writing secret message backwards.

·        Writing message vertically rather than horizontally.

·        Substituting dots for vowels.

·        Substituting special symbol for normal of alphabets.

 

A Caesar type encryption mechanism can be easily is detected by trying all possible displacements till the message becomes meaningful.

Cryptography is the process of transforming plain text or original information into an unintelligible form so that it may be sent over unsafe channels of communication.

 

Cipher systems

 

1.  
   • Transportation cipher

 

1.  
   • Code cipher……