International Journal of Computer Applications (0975 – 8887) Volume 118 – No. 7, May 2015 6 Secure Communication using RSA Algorithm for Network Environment Amrita Jain Department of Information Technology IET DAVV, Indore (M.P), India Vivek Kapoor, Ph.D Department of Information Technology IET DAVV, Indore (M.P), India ABSTRACT Secure communication in network environment is primary requirement to access remote resources in a controlled and efficient way. For validation and authentication in e-banking and e-commerce transactions, digital signatures using public key cryptography is extensively employed. To maintain confidentiality, Digital Envelope, which is the combination of the encrypted message and signature with the encrypted symmetric key, is also used. This research paper has proposed to develop a hybrid technique using Symmetric & Asymmetric key cryptography. It will also include Message authentication code to maintain integrity of message. Therefore, proposed model will not only help to maintain confidentiality and authentication of message and user but integrity of data too. Java technology has been proposed to validate the performance of proposed model in context of message length, key length, cipher text length and computational time for encryption and decryption. Keywords Hybrid Secure Communication, RSA, MAC, Symmetric Key. 1. INTRODUCTION In the current era significant computing applications have emerged in recent years to simultaneously connect millions of users to share content, form social groups and communicate with their contacts. Network Environment is the key soul such applications. To maintain security in such applications, Security mechanisms usually involve more than a particular algorithm or protocol for encryption & decryption purpose and as well as for generation of sub keys to be mapped to plain text to generate cipher text. It means that participants be in possession of some secret information (Key), which can be used for protecting data from unauthorized users. Thus basic purpose of this model is too developed within which security services and mechanisms can be viewed. The main purpose of this project is to provide an efficient way to user send or receive message over a secured channel. To maintain confidentiality and integrity of content is primary focus of proposed model. This model integrate RSA algorithm along with Diffie Hellman Key Exchange Algorithm. There are various security algorithms are available but still they have scope of improvement. For Example RSA encryption can only provide confidentiality not integrity of content. Authentication can be achieved but on the cost of big key exchange overhead. The complete study concludes to develop a security mechanism consisting confidentiality, authentication and integrity on single platform 2. LITERATURE SURVEY A method of encryption that combines two or more encryption schemes and includes a combination of symmetric and asymmetric encryption to take advantage of the strengths of each type of encryption is known as Hybrid Encryption. RSA is a cryptosystem for public-key encryption, and is widely used for securing sensitive data, particularly when being sent over an insecure network such as the Internet. RSA was first described in 1977 by Ron Rivest, Adi Shamir and Leonard Adleman of the Massachusetts Institute of Technology. Public-key cryptography, also known as asymmetric cryptography, uses two different but mathematically linked keys, one public and one private. The public key can be shared with everyone, whereas the private key must be kept secret. In RSA cryptography, both the public and the private keys can encrypt a message; the opposite key from the one used to encrypt a message is used to decrypt it. This attribute is one reason why RSA has become the most widely used asymmetric algorithm. It provides a method of assuring the confidentiality, integrity, authenticity and non- reputability of electronic communications and data storage. RSA derives its security from the difficulty of factoring large integers that are the product of two large numbers Multiplying these two numbers is easy, but determining the original prime numbers from the total -- factoring -- is considered infeasible due to the time it would take even using today’s super computers. The public and the private key-generation algorithm is the most complex part of RSA cryptography. Two large prime numbers, p and q, are generated using the Rabin-Miller primarily test algorithm. A modulus n is calculated by multiplying p and q. This number is used by both the public and private keys and provides the link between them. Its length, usually expressed in bits, is called the key length. The public key consists of the modulus n, and a public exponent, e, which is normally set at 65537, as it's a prime number that is not too large. The e figure doesn’t have to be a secretly selected prime number as the public key is shared with everyone. The private key consists of the modulus n and the private exponent d, which is calculated using the Extended Euclidean algorithm to find the multiplicative inverse with respect to the totient of n. Considering arithmetic modulo n, let’s say that e is an integer that is co prime to the totient φ(n) of n. Further, say that d is the multiplicative inverse of e modulo φ (n). These definitions of the various symbols are listed below for convenience: n = a modulus for modular arithmetic φ (n) = the totient of n e = an integer that is relatively prime to φ(n) [T his guarantees that e will possess a multiplicative inverse modulo φ(n)] d = an integer that is the multiplicative inverse of e modulo φ(n) The computational steps for key generation are 1. Generate two different primes’ p and q