Volume-03 ISSN: 2455-3085 (Online) Issue-06 RESEARCH REVIEW International Journal of Multidisciplinary June-2018 www.rrjournals.com [UGC Listed Journal] © RRIJM 2015, All Rights Reserved 381 | P age Mechanism of Signcryption – A Review * Anuj Kumar Singh Assistant Professor, Amity University, Haryana, Gurgaon (India) ARTICLE DETAILS ABSTRACT Article History Published Online: 16 June 2018 Signcryption is a relatively new way to achieve confidentiality and authentication simultaneously. Before the advent of signcryption the approach was to first encrypt and then to sign the message, but this scheme had more computational cost and communication overhead. Many signcryption schemes have been developed and implemented so far, but differ in security attributes they provide and computational cost they incur. This paper explains the mechanism of signcryption and analyzes the different cryptographic approaches which can be used along with signcryption. It also provides a glimpse of different signcryption schemes proposed. Keywords Signcryption, Mechanism, Review * Corresponding Author Email: anujbtechcs[at]gmail.com 1. Introduction The technique of Signcryption was introduced by Yuliang Zheng [1] in 1997. Signcryption is relatively a new cryptographic system which combines encryption and authentication in only one logical step. Zheng claimed that signcryption incurs 58% less computational cost and 85% less overhead in comparison to the conventional signature-then-encryption approach. Since the inception of signcryption many signcryption schemes have been given by the authors throughout the years offering different security attributes while having certain advantages and limitations. Also these signcryption schemes are based on DLP (Discrete Logarithmic Problem), ECDLP (Elliptic Curve Discrete Logarithmic Problem) or BDHP (Bilinear Diffie Hellman Problem). The mechanism of signcryption has been explained in the upcoming section of the paper. 2. Mechanism of Signcryption Signcryption mechanism has three phases namely Initialization Phase, Signcryption Phase and Un-signcryption phase [1]. a) Initialization Phase is intended to select global public parameters used by Alice (Sender) and the Bob (Receiver). The key pair for Alice and Bob is also chosen in this phase. The steps carried out are shown in Figure 1. b) Signcryption Phase enables sender Alice to send the signcrypted message to the recipient Bob. Alice selects a random integer x in the range [1, q-1]. The key k is generated and divided into two subkeys k1 and k2 of equal length, used in subsequent operations. The computations performed are shown in Figure 2. Alice sends signcrypted message (c,r,s) to Bob. c) Un-signcryption Phase - After receiving the signcrypted message (c,r,s) Bob computes the key k and divides it into two subkeys k1 and k2 of equal length. The computations are shown in Figure 3. In this way using signcryption encryption and authentication are performed in only one logical step. Figure 1: Steps in Initialization Phase Figure 2: Computations Performed in Signcryption Phase