A Publicly Verifiable Low Cost Signcryption Scheme Ensuring Confidentiality

Signcryption was first proposed by Zheng and there after several signcryption schemes have been formulated. The minimum cost of unsigncryption and public verification in the various schemes is two exponential modulo when using Discrete Logarithmic Problem (DLP). In this paper a new signcryption scheme is proposed which is more efficient than the existing schemes in terms of computational cost. The cost of unsigncryption is one exponential modulo which is lower than the Zheng´s scheme, Bao Deng Scheme and Nasr et. al scheme with an added advantage of public verification. The cost involved in public verification is also one exponential modulo and addresses the issue of confidentiality required for public verification.