SOME ID-BASED DIRECTED DIGITAL SIGNATURE SCHEMES

This book explores some ID-based cryptographic schemes using bilinear pairings over elliptic curves. In this book first we review the bilinear pairings such as Weil and Tate pairings and analyze how they can be used in the construction of ID-based cryptographic schemes. We present an efficient ID-based directed signature scheme and its associated schemes for different scenarios such as ID-based directed proxy signature scheme ID-based multisignature schemes and ID-based directed multi-proxy signature scheme. As an extension we construct threshold version for these directed signature schemes. These schemes allow a user(s) to sign on a message for a designated user. Only the designated user can directly verify the signature issued to him; and in case of trouble or if necessary he can prove the validity of signatures to any other party. All the directed signature schemes that are presented in this book are suitable for practical applications where the privacy of the signature receiver is of great concern. Finally we propose an application of directed signature scheme namely allocation of registration number in the ID-based setting using pairings.