Non-Vulnerable Data Transfer System Using Cryptography

DOI : 10.17577/IJERTV1IS8210

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Non-Vulnerable Data Transfer System Using Cryptography

Dr K Venkata Rao PhD Kalpana Mogadati

Professor, Dept. of CSE M.Tech,CSE

Vignans Institute of Information- Vignans Institute of Information – Technology Technology

Duvvada,Visakhapatnam Duvvada,Visakhapatnam

Abstract — The aim of the Paper is to provide the security during transmission of the data. Commonly used technologies are cryptography, Compression and decompression. This can be used for secure and fast sending for security purpose we are using the Cryptography technology and to increase the file transfer speed we are using the compression and decompression technologies. In this paper we described lot of processes for secure data transmission. First perform the compression and decompression techniques for

decrease the file size. It will increase the transmission speed here maintains compression and decompression technique based on the GZIP Algorithm. Than perform the cryptography technique based on the TINY Encryption Algorithm. In sending process the TCP (Transaction control protocol) was involved.

Keywords TINY, GZIP, TCP, cryptography, compression, decompression


System definition is the process of obtaining a clear understanding of the problem space such as your business opportunities; user needs, or market environment and defining an application or system to solve that problem. In the existing system, file transfer is not a secured transaction. User Profiles and access controls are not integrated to provide higher-level security in data transfer. Encryption and decryption implementation through a character user interface is a complicated process where the user or the administrator is to follow some complex process.

The information generated at the client side while under the standard of transfer should be secure enough and protected by any intrusions and interceptions that may occur while the information is transferred. The overall system should concentrate

on the best algorithm that can be implemented for al the resource standards that can be implemented as per the standards of the technical quality.

In the traditional 2tierarchitecture there existed only the server and the client. In most cases the

server was only a data base server that can only offer data. Therefore majority of the business logic i.e., validations etc. had to be placed on the clients system. This makes maintenance expensive. Such clients are called as fat clients. This also means that every client has to be trained as to how to use the application and even the security in the communication is also the factor to be considered.

Since the actual processing of the data takes place on the remote client the data has to be transported over the network, which requires a secured format of the transfer method. How to conduct transactions is to be controlled by the client and advanced techniques implementing the cryptographic standards in the executing the data transfer transactions. Present day transactions are considered to be "un-trusted" in terms of security, i.e. they are relatively easy to be hacked. Nevertheless, sensitive data transfer is to be carried out even if there is lack of an alternative. Network security in the existing system is the motivation factor for a new

system with higher-level security standards for the information exchange to provide ease and secured file maintenance and management in a distributed environment.

So in this paper we are going to propose that the system should have the following features: The transactions should take place in a secured format between various clients in the network. The validation code should be placed on the server and not on the client such that file transfer takes place between only the registered users only. This leads to a thin client, which is more desirable. The server should identify the type of request (GET/POST), file access permissions and perform appropriate action. It should also identify the user and provide the communication according to the prescribed level of security with transfer of the file requested and run the required process at the server if necessary. When responding to the client, the server should send necessary information such as User authorization and authentication information, Encryption, Decryption types and their level of hierarchy etc.


In this paper we are going to focus on this following techniques in-order to send the data securely using cryptography.

Compress and Decompress Technique:

This technique maps arbitrary input into printable character output. The form of encoding has the following relevant characterstics.

The range of function is a character set that is universally re-presentable at all sites, not a specific binary encoding of the character set. Thus, the characters themselves can be encoded into whatever form is needed by a specific system .For instance, the character is represented in ASCII system as a hexadecimal hexadecimal 45 and in EDCDIC- based system a hexadecimal- c5.The character set consists of

65 printable characters, one of which is used for padding. With 2^6 = 64 available characters, each character can be used to represent 6 bits of input.

No control characters are included in the set. Thus, the message encoded in Radix-64 can traverse mail- handling system. That scans the data stream for control characters. The hyphen character "- " is not included

CryptographyTechnique (TinyEncryption)

The Tiny Encryption A l g o r i t h m ( TEA) is a cryptographic algorithm designed to minimize memory footprint and maximize speed. It is a Feistel type cipher that uses operations from mixed (orthogonal) algebraic groups. This research presents the

cryptanalysis of the Tiny Encryption Algorithm. In this research we inspected the most common methods in the cryptanalysis of a block cipher algorithm. TEA seems to be highly resistant to differential cryptanalysis, and achieves complete diffusion (where a one bit difference in the plaintext will cause approximately 32-bit differences in the cipher text) after only

six rounds. Time performance on a modern desktop computer or workstation is very impressive.

As computer systems become more pervasive and complex, security is increasingly important. Cryptographic algorithms and protocols constitute the central component of systems that protect network transmissions and store data. The security of such systems greatly depends on the methods used to manage, establish, and distribute the keys

Employed by the cryptographic techniques. Even if a cryptographic algorithm is ideal in both theory and implementation, the strength of the algorithm will be rendered useless if the relevant keys are poorly managed.

The following notation is necessary for our discussion.

  • Hexadecimal numbers will be subscripted withh,e.g.,10=16h

    Bitwise Shifts: The logical shift of x by y bits is denoted by x << y. The logical right shift of x by y bits is denoted by x >> y.

    Bitwise Rotations: A left rotation of x by y bits is denoted by x <<< y. A right rotation of x by y bits is denoted by x >>> y.

    Exclusive-OR: The operation of addition of n- tuples over the field (also known as 2F exclusive-or )is denoted by xy

    The Tiny Encryption Algorithm is a Fiestel type cipher that uses operations from mixed (orthogonal) algebraic groups. A dual shift causes all bits of the data and key to be mixed repeatedly. The key schedule algorithm is simple; the 128-bit key K is spli into four 32-bit blocks K = ( K[0], K[1], K[2], K[3]). TEA seems to be highly resistant to differential cryptanalysis and achieves complete diffusion (where a one bit difference in the plaintext will

    cause approximately 32

    bit differences in the cipher text). Time performance on a workstation is very impressive.

    Block ciphers where the cipher text is calculated from the plain text by repeated application of the same transformation or round function. In a Feistel cipher, the text being encrypted is split into two halves. The round function, F, is applied to one half using a sub key and the output of F is (exclusive- or-ed (XORed)) with the other half. The two halves are then swapped. Each round follows the same pattern except for the last round where there is often no swap. The focus of this thesis is the TEA Feistel Cipher

    The inputs to the encryption algorithm are a plaintext block and a key K .The plaintext is P = (Left[0], Right[0]) and the cipher text is C =(Left[64], Right[64]). The plaintext block is split into two halves, Left[0] and Right[0]. Each half is used to encrypt the other half over 64 rounds of processing and then combine to produce the cipher text block.

  • Each round i has inputs Left[i-1] and Right[i-1], derived from the previous round, as well as a sub key K[i] derived from the 128 bit overall K.

  • The sub keys K[i] are different from K and from each other.

  • The constant delta =(51/2-1)*231 =9E3779B h, is derived from the golden number ratio to ensure that the sub keys are distinct and its precise value has no cryptographic significance.

  • The round function differs slightly from a classical Fiestel cipher structure in that integer addition modulo 2³² is used instead of exclusive-or as the combining operator

Fig:2 Internal Details of TEA

Above Figure2 presents the internal details of the

ith cycle of TEA. The round function, F, consists of the key addition, bitwise XOR and left and right shift operation. We can describe the output (Left[i

+1] , Right[i +1] ) of the ith cycle of TEA with the input (Left[i] ,Right[i]) as follows Left [i+1] = Left[i] F ( Right[i], K [0, 1], delta[i] ),Right [i +1] =

Right[i] F ( Right[i +1], K [2, 3], delta[i] ), delta[i]

= (i+1)/2 * delta,

The round function, F, is defined by F(M,K[j,k],delta[i])=((M<<4)K[J](M


The round function has the same general structure for each round but is parameterized by the round sub key K[i].The key schedule algorithm is simple;the 128-bit key K split into four 32-bit blocks K=(K[0],K[1],K[2],K[3]).The keys K[0] and K[1] are

used in the odd rounds and the keys K[2] and K[3] are used in even rounds.

Fig3:structureof the TEA decryption routine

Decryption is essentially the same as the encryption process; in the decode routine the cipher text is used as input to the algorithm, but the sub keys K[i] are used in the reverse order.

Fig.3 presents the structure of the TEA decryption routine. The intermediate value of the decryption process is equal to the corresponding value of the encryption process with the two halves of the value swapped. For example, if the output of the nth encryption round is

ELeft[i] || ERight[i] (ELeft[i] concatenated with ERight[i]).

Then the corresponding input to the (64-i)th decryption round is

DRight[i] || DLeft[i] (DRight[i] concatenated with DLeft[i]).

After the last iteration of the encryption process, the two halves of the output are swapped, so that the cipher text is ERight[64] || ELeft[64], the output of that round is the final cipher text C. Now this cipher text is used as the input to the decryption algorithm. The input to the first round is ERight [64] || ELeft [64], which is equal to the 32-bit swap of t h e o u t p u t of t h e 6 4 t h round of the Encryption process.


In this paper we address how Compression & decompression support security and cryptography to the data .For fast transmission of date and for Security reasons we use compression & decompression techniques. The performs of

compression decompression techniques for Decrease the file size has been implemented which will increase the transmission speed. Here we managed

to maintain compression and decompression technique based on the GZIP Algorithm

and performed the cryptography technique based on the TINYEncryption Algorithm .So the security can be more provided with this technique during transmission of data.


  1. J o a n Daemen and Vincent Rijmen, AES Submission document on Rijndael, June 1998.

  2. [Rijn99]Joan Daemen anVincent Rijmen,AES submission document onRijndael,Version 2, September 1999. [3] J o a n Daemen and Vincent Rijmen, the Design of Rijndael, AES – The Advanced Encryption Standard, Springer-Verlag 2002 (238 pp.)

  1. [DaKnRi97] J. Daemen, L.R. Knudsen and V. Rijmen, "The block cipher square," Fast

    Software Encryption, LNCS 1267, E. Biham, Ed., Springer-Verlag, 1997, pp. 149-165.

  2. [KeScWa96] J. Kelsey, B. Schneier and D. Wagner, "Key-schedule cryptanalysis of IDEA, GDES, GOST, SAFER, and Triple-DES," Advances in Cryptology, Proceedings Crypto

'96, LNCS 1109, N. Koblitz, Ed., Springer- Verlag, 1996, pp. 237-252.

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