International Research Journal of Engineering and Technology (IRJET) Volume: 04 Issue: 02 | Feb -2017
e-ISSN: 2395 -0056
www.irjet.net
p-ISSN: 2395-0072
ANALYSIS OF SYMMETRIC KEY CRYPTOGRAPHIC ALGORITHMS SurekhaThorat1 Rohini Sharma 2 Shivaji Pansare3 --------------------------------------------------------------------****-------------------------------------------------------------------------
Abstract: Today information has become the most powerful commodity & communication online or through wireless network .Also there are number of financial and personal data application developed but real need of security because there are various passive and active attacks. We use typical security mechanism like password security or encoding data .Cryptography is best solution for security .Cryptography means encoding message in non readable format it is called encryption and convert message in to non readable to readable format called decryption .This paper represent analysis of various symmetric key cryptographic algorithms .
Keywords : Symmetric key algorithm ,DES DOUBLEDES,IDEA,AES,RC4,RC5,RC6, Blowfish 1.INTRODUCTION Today transaction and Exchanging data using internet is become very efficient part of day to day life. Variety of Confidential data is exceeded through internet which include defense record, password, bank related data, medical records personal information etc. These information should always be protected from hackers .There are various encryption algorithm are used for data protection .Cryptography algorithm play important role in data protection .In cryptography message hidden from unauthorized user and only Authorized recipient will able to convert it into original message. There are Symmetric Encryption algorithms and asymmetric algorithm both are play important role in information security. If encryption algorithm take long time for execution then it is useless. Today more and more sensitive data is being stored on computers and transmitted over the Internet. So we need security and safety of information. In this paper We discuss about different Symmetric key Cryptography Algorithm.
2. SYMMETRIC KEY CRYPTOGRAPHY ALGORITHM Here same secrete key is used for encryption and decryption .but big problem here key distribution /key exchange using same key .Sender and receiver use same secrete key which is hidden and this key is use for encryption and decryption but both the parties must agree upon the key before any transaction begins and nobody else should know about it .If anyone get this key easily obtained hidden message. Plain text message, secrete key, cipher text message and Symmetric algorithm for encryption and decryption play important role in cryptography model. 2.1 Overview of Some Common Symmetric Algorithm There are two types of encryption algorithms stream ciphers provide bit by bit and block cipher provide block by block encryption. A. Data Encryption Standard (DES) It is generally used in ECB,CBC,CFB mode. It was designed by IBM based on their Lucifer Cipher[10]. The origin of DES go back to 1972 by National Institute of Standards and Technology (NIST) and embarked a DES encrypt data in block of size 64 bits each .It has input 64 bits of plain text and produce 64 bits cipher text output.Before DES process start every eight bit of the key is discarded to produce 56-bit key .It use substitution and transposition .[9]It contain 16 round .First it perform initial permutation function(IP).IP happens only once before round start .IP produce two halves LPT and RPT .Each half block consist of 32bits.Then start round first operation is key transformation which generate 48 bit sub key from 56 bits. Then Expansion permutation perform on RPT is expanded from 32 bits to 48 bits .Then 48 bit key is XORed with 48 bit RPT and then resulting output is given to S-box substitution .It accept 48 bit input and expand RPT and produce 32 bit output. Last stage is p-box permutation. Output of 32 bits is permuted using P-box. All these steps perform on 32 bit RPT .Here LPT are untouched so at these stage LPT XORed with output produced by p-box permutation. Then get new right half .At the end of 16 rounds Final permutation is performed by using simple transposition techniques. It had been also observed that decryption of DES algorithm is better than other symmetric algorithms in throughput and less power consumption[1] B.Double DES It perform twice what DES normally does once . It use 64 bit plain text block and 56 bit key. So we will need to store 256 64 bit block to store the table in memory. There are chances of Meet in the middle attack. C.International Data Encryption Algorithm (IDEA ) It was launched in1990.It required licensed before it can use in application .Also it has tracking record .IDEA is block cipher.It has input as 64 bit plain text block and use 128 bit longer key .Input divided into four portion .Then perform eight rounds .Last step is output transformation .IDEA use 128 bit key which is double than DES So it required 2128 operation and which is very difficult to break IDEA [10]. Today, in many market areas,
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