Techniques Practiced in Identity-based Cryptography and Applications Ms. Amrita Kungwani(Author) Dept. of Computer Science and Engineering Jhulelal Institute of Technology Nagpur, India Dr. C. S. Warnekar (Author) Dept. of Computer Science and Engineering Jhulelal Institute of Technology Nagpur, India Abstract— With regards to confidentiality, cryptography is used to encrypt data residing on storage devices or traveling through communication channels to avoid any illegal access. Also, cryptography is used to secure the process of authenticating the parties which attempt any function on the system. Since a party wishing be granted a certain functionality on the system must present something as a proof that they indeed who they say they are. That something is sometimes known as credentials and additional measures must be taken to ensure that these credentials are only used by their authorized owner. The most classic credential used is passwords. Passwords are stored in encrypted format to protect against illegal usage. Identity Based Cryptography is an important concept of public key cryptography. Elliptic Curve is now being used in designing many cryptographic protocols. Pairing based protocols are used in many protocols and pairing has found applications in the solution of ID – based Cryptographic schemes and short signature schemes. Pairing-based cryptography does pairing between elements of two cryptographic groups to a third group with a mapping e: G1 * Gs -> GT to construct or analyze cryptographic systems. Keywords— Identity based Cryptography, Public Key, Private key, authorisation, digital signature. I. INTRODUCTION Identity-Based (IB) cryptography is an emerging approach to public-key cryptography that does not require principals to pre-compute key pairs and obtain certificates for their public keys instead, public keys can be arbitrary identifiers such as email addresses, while private keys are derived at any time by a trusted private key generator upon request by the designated principals. Identity Based Cryptography is used to secure the process of authenticating the parties which attempt any function on the system. This technique is dependent on the identity of the user. The identifier information of the user i.e. IP Address, email or mobile number instead of digital certificates can be accepted and used as public key for signature verification or encryption. The previously available scheme like RSA is more complex because it requires two prime numbers with some conditions leading to difficulty in find a couple of numbers as initiator of keys for millions of users. This complexity and difficulties of public key encryption is reduced by the process called identity-based cryptography, which significantly reduces the system complexity and the cost for establishing and managing the public key authentication framework. The idea of IB cryptography was emerged in 1984, although only an IB signature (IBS) scheme was then suggested, based on conventional algebraic methods in Zn. Other IBS and identification schemes were convenient to follow. However, it is only in 2001, a practical IB encryption (IBE) mechanism was Ultimately suggested, based on the much heavier machinery of bilinear pairings on elliptic curves, whose use in cryptography had slowly started to surface in the few years prior, e.g., for key exchange and IBS. II. CONCEPT OF IDENTITY BASED CRYPTOGRAPHY SYSTEM In the IBE scheme, the sender Alice can use the receiver's identifier information which is represented by any string, such as email or IP address, even a digital image, to encrypt a message. Bob(receiver), having obtained a private key associated with his identifier information from the trusted third party called the Private Key Generator (PKG)", can decrypt the cipher text. Fig 1: Identity-Based Encryption Summing up, we describe an IBE scheme can be illustrated using the following steps. 1. Setup: The PKG generates its master (private) and public key pair, which we denote by skPKG and pkPKG respectively. 2. Private Key Extraction: Bob (receiver) authenticates himself to the PKG and obtains a private key skIDBob associated with his identity IDBob. 3. Encryption: Alice uses Bob's identity IDBob and the PKG's pkPKG to encrypt her plaintext message M and obtains a cipher text C. International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 Published by, www.ijert.org ICSTS-2015 Conference Proceedings Volume 3, Issue 24 Special Issue - 2015