International Journal of Pure and Applied Mathematics Volume 119 No. 12 2018, 16613-16621 ISSN: 1314-3395 (on-line version) url: http://www.ijpam.eu Special Issue ijpam.eu

A SECURED APPROACH FOR USING MULTILEVEL

Sumathi.R , N.R.Raajan School of Electrical and Electronics Engineering, SASTRA UNIVERSITY- 613402

ABSTRACT: These days, the term ‘security’, plays a vital role in every common man’s life .Life without internet and online transactions is highly impossible. Hence, there is a great scope for strong encryption schemes which provide security to the data. In this paper we have proposed a multilevel encryption scheme which will enhance the security of the data.

I. INTRODUCTION: Providing ‘security ‘to the data that is being transmitted over the internet plays a vital role. There are many conventional encryption methods that are available to keep the information safe .Complete Security[2] is said to be provided only when the data is safe and also when the system does not allow any intruder to be successful in attempting to hack the data. In this paper, we have a proposed an encryption scheme that would enhance the security offered to the data.

II. RELATED WORK:

Useful data is always converted into unreadable form in the process of encryption[1]. This process of conversion should not be vulnerable to attack. There are many different methods for obtaining the encrypted data viz... , Caesar’s method, poly alphabetic substitution, bit level encryption etc. Encryption can also be achieved using multilevel encryption schemes. Irrespective of the schemes used, there are always intruders who use the techniques to break most of the encryption schemes used. Intruders and eave’s droppers have almost succeeded in breaking most of the encryption algorithms used in prime fields as in banks, military, defense. Hence, there is a very strong need to

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strengthen up the security system. As a part of this, this paper proposes a scheme which uses randomized encryption there by not giving any clue to the intruder about the encryption pattern.

III. PROPOSED SYSTEM:

Proposed system makes use of multiple levels of encryption. The system makes use of six algorithms for the encryption process. All the six algorithms are identified with a unique number allocated to them respectively. The user is given a choice to select four algorithms out of the six to carry out encryption.

The details of the choice of the algorithms made are given as an input the pseudo random generator[16-17] which will then generate a random sequence. The order of the execution of the algorithms will take place as per the sequence generated. The sequence generated being completely random in nature contributes majorly to the enhancement of the security offered to the data. The output of each algorithm acts as an input to the other.

The decryption of the data is done in an exactly opposite manner. The execution of algorithms here, takes place in a reverse way to that of the encryption.

The six algorithms used here are : A. [10] B. Vigenere Cipher [10] C. Vernam Cipher[14]

D. Play-Fair Cipher [11] E. Rail-Fence Cipher [11] F. Trifid Cipher[13]

IV. PROCESS FLOW- WORKING OF SYSTEM:

Input Text(Secret Text)

Choice of Algorithms(6)

Pseudo Random Generator

Random sequence (4 digits)

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Algorithm 1

Algorithm 2

Algorithm 3

Algorithm 4

(ENCRYPTION )

Link

Fig 1: Process flow for the encryption process of the proposed system

Random sequence Link (4 digits)

Algorithm 4

Algorithm 3

Algorithm 2

Algorithm 1

(DECRYPTION )

Input text (Secret Text)

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Fig 2: Process flow for the decryption process of the proposed system

A. CAESAR CIPHER:

Caesar cipher is also known by the names shift cipher, Caesar’s or Caesar shift. The principle of working involves shifting all the letters in the given piece of text by a certain number of places. The number of shifts to be done is based on a letter which is taken as a reference .This acts as the for this algorithm.

For example, the reference letter A implies “no shift”, B implies “shift by one place” and so on. For example, the word “CAESAR” with a shift P becomes “RPTHPG”.

B. VIGENERE CIPHER:

Vigenere cipher takes another name called poly alphabetic cipher. The key is a group of letters whose length is equal to that of the plaintext. The first letter of the key and the first letter of the plaintext are paired up to get the first key which will indicate the number of shifts to be done. Similarly all the letters in the key are paired with the respective letters in given plaintext to know the number of shifts to be done for the respective letters and finally the encrypted data is obtained.

For example, the first letter of the plain text, A, is paired with L and the corresponding number of shifts is done. Similarly, the second letter of the plaintext, T, is paired with the second letter of the key, E and the shift in the position is done accordingly. The same procedure is carried out for the remaining letters in the plain text to obtain the cipher text. Plaintext: ATTACKATDAWN Key: LEMONLEMONLE

Cipher text: LXFOPVEFRNHR

C. VERNAM CIPHER:

This is one of the many secured algorithms which offers good security .It is also known as one time pad. Like the Vigenere cipher, the length of the message and the key remains the same. Unlike it, the message and the key are represented as a stream of 0’s and 1’s. The bit stream for the message is obtained using ASCII coding mechanism and that of the key is just a random combination of 0’s and 1’s. The two bit streams are XORed to get the encrypted text. The security lies in the random combination of 0’s and 1’s used in the key.

D. PLAY-FAIR CIPHER:

Play fair are a type of , the cipher text character that replaces a particular plaintext character in the encryption will depend in part on an adjacent character

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in the plaintext. They are named for an English lord, Lyon Play fair, who advocated their use, but they were invented by Charles Wheatsone.

Encryption is accomplished using a square array of characters, constructed from the encryption key. Because our set of plaintext characters is the 26-letter English alphabet, for us this array will be 5x5 , with 2 of the 25 characters occupying a single position in the array.

E. RAIL-FENCE CIPHER:

It is kind of and is also known as zigzag cipher. An anagram is created effectively by rearranging the letters of the plaintext. It get’s the name rail fence, as the message is written downwards across the successive rails of a fence that is imaginary.

F. TRIFID CIPHER:

Trifid ciphers are examples of combination ciphers. The encryption process consists of a sequence of several different techniques. In this case substitution followed by fractionation and transposition are used in the encryption. The trifid cipher was invented by amateur cryptographer Felix Delastelle, ca.1900.Trifid use a b by 3 by 3 key cube.

The encryption key for the trifid cipher consists of a positive integer and a 3x3x3 array containing all of the distinct letters of the English alphabet plus one additional character. Typically, the additional character in the array is a symbol, such as a dot. The arrangement of the characters in the key array can be chosen at random.

V. SIMULATION:

The following set of screen shots shows the encryption and decryption of text files. Simulation is tested and verified using Java Platform.

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Fig 3.1: Pseudorandom generator output

The above figure shows a random sequence generated by the pseudorandom generator based on the choice of the algorithms made by the user.

Fig 3.2 Sample output

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The above figure shows the sequence of the algorithms executed from the choice made. The respective encrypted and decrypted outputs after the data is passed through each and every algorithm are also displayed.

VI. CONCLUSION:

The encrypted data in the proposed system is obtained based on the random sequence generated by the pseudo random generator which in turn primarily depends on the choice of the algorithms made by the user. It is highly difficult for any eve’s dropper or hacker to guess the sequence generated. Also, the choice of algorithms made differs from user to user. The sequence generated for every combination of the algorithms chosen is random, that is it cannot be predicted easily. This makes the hacker go absolutely clueless about the way the data has undergone encryption. Hence there is a lot of uncertainty involved. This uncertainty strengthens the security offered to the data.

REFERENCES:

1. Sairam Natarajan #1, Manikandan Ganesan *2, Krishnan Ganesan #3, A Novel Approach for Data Security Enhancement, Sairam Natarajan et al, / (IJCSIT) International Journal of Computer Science and Information Technologies, Vol. 2 (1) , 2011, 469-473 2. W. Stallings, “Cryptography and Network Security: Principles and Practices, 2nd ed”., Prentice Hall, 1999. 3. Walter Tuchman , "A brief history of the data encryption standard",Internet besieged:countering cyberspace scofflaws. ACM Press/Addison-WesleyPublishing Co. New York, NY, USA, pp. 275– 280,1997.

4. William E. Burr, "Data Encryption Standard", in NIST's anthology",A Century of Excellence in Measurements, Standards, and Technology: A Chronicle of Selected NBS/NIST Publications,2000. 5. Joan Daemen, Vincent Rijmen, "The Design of Rijndael: AES - The Advanced Encryption Standard." Springer, 2002. 6. Nicolas Courtois, Josef Pieprzyk, "Cryptanalysis of Block Ciphers with Overdefined Systems of Equations", pp267–287, ASIACRYPT 2002. 7. Christof Paar, Jan Pelzl, "The Advanced Encryption Standard", Chapter 4 of " Understanding Cryptography,A Textbook for Students and Practitioners ",Springer, 2009. 8. Rivest, R.; A. Shamir; L. Adleman ,"A Method for Obtaining Digital Signatures and Public-Key ", Communications of the ACM 21 (2): 120–126,1978. 9. Si,Abraham;Paul L.Irwin,”Elementart Cryotanalysis: A Mathematical Approach”, Mathematical Association of America.pp.13-15,1966. 10. David Bishop, Introduction to Cryptography with JavaTM Applets”, Jones and Barlett Publishers, 2003. 11. Atul Khate,”Cryptography and Network Security”, third edition,McGraw Hill Education,2013. 12. Peter Thorsteinson , Gnana Arun Ganesh, “.NET Security and Cryptography”, Prentice Hall 13. William Maxwell Bowers,”Trifid Cipher”, American Association. 14. Helen Fouche Gaines, A Study of ciphers and their solution”, Dover Publications,Inc 15. Yaacov Apelabaum,,” User authentication principles, theory and practice”, Technology press, second edition. 16. Julio Sanchez, Maria P Canton , “ Java Programming for Engineers”,CRC Press. 17. Khalid A.Mughal, Troill Hamre and Rolf W.Rasmussen, “JAVA actually, A First course in programming”,Thomson Learning, 2007. 18. Dr. E. Balamurugan, M.Sc., M.Phil., PhD ELLIPTIC CURVE INTEGRATED ENCRYPTION SECEME USING ANALYSIS VEHICULAR AD HOC NETWORK International Journal of Innovations in Scientific and ISSN: 2347-9728(print) Engineering Research (IJISER)

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