“ Cryptography”
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“Cryptography”
Why Cryptography ?
We all know that now a day this is the world of information technology and almost everyone have to communicate with each other. Most of the time this communication occurs on the network. During the communication of data it may be possible that the data we are sending or receiving can be hacked or edited by someone. The data we are communicating may be bank a/c number, passwords or some important files etc. To protect the data from this type of unwanted things “Cryptography” is very useful.
ABSTRACT This project is all about providing security while communicating any data on the network between two or many user. We are going to discuss about the main ciphers used in Cryptography in this project.
There are various techniques of encryption and decryption which are used in this project such as
Shift or Substitution cipher Monoalphabetic cipher Playfair cipher Vegenere cipher
Within the context of application-to-application communication, there are some specific security requirements, including:
Authentication Privacy/Confidentiality Integrity Non-repudiation
Cryptography, then not only protect data from theft or alteration, but can also be used for user authentication.
There are, in general two types of Cryptographic schemes typically used to accomplish these goal:
(1) Private–key ( or symmetric ) cryptography (2) Public-Key ( or asymmetric ) cryptography
In all the cases,
The initial unencrypted data is referred to as “plaintext”. The encrypted data is referred to as “cipher text”. (which will in turn (usually) be decrypted into usable plaintext)
Content 1. Introduction 1.1 Introduction to Cryptography 1.2 Types of Cryptographic Algorithm 1.2.1 Secret key Cryptography 1.2.2 Public Key Cryptography 1.2.3 Hash Function
2. Purpose
3. Objective
4. System Specification Hardware Software
5. Future Scope
6. Conclusion
Introduction The word cryptography or cryptology comes from an Ancient Greek. The word
cryptology is made of two components ”crypto”, which means hidden or secret and “logos” which means word. It is a Science of writing in secret code. Cryptography is the study of techniques for secure communication.
There are two important concepts of cryptography, first one is Encryption & the second one is Decryption. Encryption is the process in which the plain text is changed into cipher Text & decryption is just reverse process of encryption that means cipher text is changed into plain text. There are various techniques of Encryption & Decryption which are used in this project such as Shift Cipher, Playfair Cipher, Monoalphabetic Cipher, Vanier Cipher.
We use the term cryptography to refer to the science and art for transforming message to make them secure from attacks.
The original message before being transformed is called ”Plaintext”. After the message
is transformed is called ”Ciphertext”. An encryption algorithm transform the Plaintext into Ciphertext & a decryption algorithm transforms the Ciphertext back into Plaintext.
Encryption Decryption
#%GIUYRWKMN,S:{?
Hello World! Hello World!( ciphertext )
( Plaintext ) ( Plaintext )
( Shared Secret Key )
Objective1. To deve lop a so f tware in wh i ch we w i l l i nput :
i) F i l es ii) Messages
and we w i l l ge t enc rypted fi les o r messages . 2. The enc rypted in format ion can be used in the ne twork ( l oca l o r i n te rne t ) i n a sa fe and secured way
3. The so f tware can a l so be used to dec rypt the enc rypted data
i n the o r ig ina l fo rm
4 . User w i l l be ab le to use the i r own keys to enc rypt the data .
SYSTEM SPECIFICATION
SOFTWARE REQUIREMENTS : OPERATING SYSTEM : WINDOWS XP / 7 FRONT END : C#.net BACK END : SQL Server
HARDWARE REQUIREMENTS : Processor : Pentium IV & above Processor Speed : 1 G Hz RAM : 2 GB Hard Disc : 10 GB
TABLES
COLUMNS DATA TYPE SIZE
Member_id int
Password char 20
Security Question char 30
Security Answer char 20
L O G I N TA B L E :
(FOREIGN KEY)
MEMBER DETAIL TABLE
COLUMNS Data Type Size
Member_id int
Name char 20
Mobile char 10
Email_id char 30
Address Char 50
(Primary Key)
LOG TABLE
Columns Data Type Size
Member_id int
File name char 20
Data datetime
Type char 10
(FOREIGN KEY)
Encryption & Decryption
ER DIAGRAM
MEMBER LOGSIN LOGIN
History
Record
LOG
MEMBERid
Name
Mob no.
Emailid
Password
SecurityQuestion
Security
AnswerAddre
ss
MEMBERid
Memberid
FileName
Data
Type
TYPES OF CRYPTOGRAPHIC ALGORITHMS
There are several ways of classifying cryptographic algorithm.
Defined by their application and use. The three types of algorithms
that will be discussed are as follows.
1. Secret key Cryptography(SKC)
2. Public Key cryptography(PKC)
3. Hash Function
SECRET KEY (SKC)Single key used to encrypt and decrypt .
Key must be known by both part ies.
Encrypt Decrypt
S a m e K e y i s u s e d t oE n c r y p t a n d D e c r y p t d a t a
Sender Recipient
Shared Secret Key
Plaintext
Ciphertext Plaintext
PUBLIC KEY (PKC)Two different keys are used in this cryptography
One key is used for encryption & other for decryption
Encrypt Decrypt
D i ff e r e n t K e y s a r e u s e d t oE n c r y p t a n d D e c r y p t d a t a
Sender
Recipient
Recipient Public Key
Recipient Private Key
Plaintext
Ciphertext
Plaintext
HASH FUNCTION Hash is a function which is used to compress the
string.
The input in the hash function is known as “Message” and output is called “Digest”.
Hash functions have four main properties : It is easy to compute the hash value for any given
message. It is infeasible to generate a message from its hash. It is infeasible to modify a message without changing the
hash. It is infeasible to find two different message with the
same hash.
Message( variable
size )
HASH
Digest( fixed size )
Our project(system) can do the cryptography by encrypting and decrypting data. We are dependent on other mailing systems Like – gmail, yahoo etc for information transfer.
In future we can add the information transfer module so that after encryption users can transfer information by the same software.
Future scope
Finally, we can say that in this project development we have learnt a lot and during the process we will get the chance to explore cryptography and the concepts involved.
CONCLUSION
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