Cryptography Greek origin and The world cryptographic has is combination of two Greek words has Crypto & Graph .Which means secret and writing .Crypto is the science of converting a stream of text into Coded form .Cryptography plays an important roll in internet based commercial activities as many secret document which include payment details, money transfer and other confidential information are to be transferred from one computer to another.
“ Cryptography is a technique that allows a piece of information to be converted into cryptic from before being stored in the computer database or transmitted over an insecure channel.” Cryptography
Model of cryptography The cryptography have use the model. Which have use the following terms in the cryptography system. <ul><li>Intruder- Intruder is a person who is not authorized to access the information. </li></ul><ul><li>Plain text- Decryption message that is to be converted into encrypted message. </li></ul><ul><li>Cipher text- Message is an encrypted form. </li></ul><ul><li>Encryption- Process of converting plain text to cipher text. </li></ul><ul><li>Decryption- process of converting cipher text to plain text. </li></ul><ul><li>Key- Parameter (process) required for conversion of the message. </li></ul>
Process of cryptographic system The sender converts the plain text into coded version by encryption for transmission over a communication channel Sender uses a key to converts plain text into a cipher text .The recipient of the cipher text will require the key to decrypt the message after decryption, the receiver will get the cipher text converted into plain text. <ul><li>If the for encryption and decryption is the same, then it is called Symmetric key . </li></ul><ul><li>If the key for both encryption and decryption are different , then the key is called Asymmetric key . </li></ul><ul><li>The sender of the documents encrypts it with a key ks (encryption key). the cipher text may be represented as </li></ul><ul><li>Cipher Text=E*ks (Documents) </li></ul><ul><li>After the cipher text has been received the receiver will use the decryption key (ks) to decrypt the cipher text. This process of decryption will convert text into the original documents </li></ul><ul><li>Document=D*ks (Cipher text) </li></ul>
Types of Cryptography The cryptography system may be categorized into two types, which are given- <ul><li>Conventional cryptographic system. </li></ul><ul><li>Modern cryptographic system. </li></ul>
Modern Cryptographic System Modern cryptographic systems are more advanced and are based on exhaustive search mechanism. The information storage, retrieval Communication and processing is done in digital media. These systems are used binary information. The plain text and cipher text are to be represented in binary codes. In these systems a cipher text may be decrypted only by using a decryption key and be encrypted only by using an encryption key.
Conventional Cryptographic System Conventional cryptographic systems are based on the encryption message text written in plain language. These systems primarily use the substitution method. The substitution method, various characters are replaced from the text by a another character. There has to be a one to one correspondence between the symbols to be replaced and the replacement symbol.
STRUCTURE OF BASIC NODE INCLUDE CRYPTOGRAPHY Plain text Cipher text Sender Plain text Cipher text Receiver
References <ul><li>G.Dhanore (Management of E-Commerce ) </li></ul><ul><li>James Dohare (E-Commerce) </li></ul><ul><li>Gupta & Jain (E-commerce With issues technology) </li></ul><ul><li>William Stallings (Complete Reference Of Electronic-Commerce) </li></ul>
Thanking you <ul><ul><ul><li>Vinod Kumar Gupta </li></ul></ul></ul><ul><ul><ul><li>B.Sc. (Hons.) I.T.A. 5 th Sem. </li></ul></ul></ul>