Identity-Based Cryptography and Comparison with traditional Public key Encryption : A Survey

In this paper, we survey the state of research on identity-based cryptography(IBC) and compare it with the traditional public key encryption. IBC is an emerging area of public key cryptography. We first reviewing the basic concepts of IBE and identity based signature(IBS) schemes, and subsequently review some important IBE schemes based on the bilinear pairing, a computational primitive widely used to build up various identity-based cryptographic schemes in the current literature. We Compare IBE with the traditional public key encryption. Finally, we discuss advantages and disadvantages of IBC with applications of IBC KeywordsIdentity based cryptography, Public key infrastructure. I.INTRODUCTION In 1984, Shamir [1] proposed a concept of identity-based cryptography. In this new paradigm of cryptography, user’s identifier information such as email address, IP addresses, social security number, a photo, a phone number, postal address etc., instead of digital certificates can be used as public key for encryption or signature verification. As a result, identity-based cryptography significantly reduces the system complexity and the cost for establishing and managing the public key authentication framework known as Public Key Infrastructure (PKI). Although Shamir [1] easily constructed an identity-based signature (IBS) scheme using the existing RSA [2] function, he was unable to construct an identity-based encryption (IBE) scheme, which became a long-lasting open problem. Only in 2001, Shamir's open problem was independently solved by Boneh and Franklin [3] and Cocks [4]. Thanks to their successful realization of identity-based encryption, identity-based cryptography is now hot area within the research community. II BASIC CONCEPTS OF IDENTITY BASED ENCRPTION AND SIGNATURW In this section we discuss the requirements of the Identity based encryption and Identity based signature A. Identity based signature As mentioned earlier, in the IBE scheme, the sender Alice can use the receiver's identifier information which is represented by any string, such email address, IP addresses, social security number, a photo, a phone number, postal address etc., to encrypt a message. The receiver Bob, having obtained a private key associated with his identity information from trusted third party called the “Private KeyGenerator (PKG)", can decrypt the ciphertext. Summing up, we describe an IBE scheme using the following steps. (Figure 1 illustrates a schematic outline of an IBE scheme). Setup: The PKG creates its master (private) and public key pair, which we denote by skPKG and pkPKG respectively. (Note that pkPKG is given to all the interested parties and remains as a constant system parameter.) Private Key Extraction: The receiver Bob authenticates himself to the PKG and obtains a private key skIDBob associated with his identity IDBob. Encryption: Using Bob's identity IDBob and the PKG's pkPKG, the sender Alice encrypts her plaintext message M and obtains a cipher text C. Decryption: Upon receiving the cipher text C from Alice, Bob decrypts it using his private key skIDBob to recover the plaintext M. B. Identity based signature. As a mirror image of the above identity-based encryption, one can consider an identity-based the signature (IBS) scheme. In this scheme, the signer Alice first obtains a signing (private) key associated with her identifier information from the PKG She then signs a message using the signing key. The verifier Bob now uses Alice's identifier information to verify Bob's signature. (Figure 2 illustrates a schematic outline of an IBS scheme.) Girish et al, / (IJCSIT) International Journal of Computer Science and Information Technologies, Vol. 5 (4) , 2014, 5521-5525