An Improved ID-Based Multi-Proxy Multi-Signcryption Scheme

In 2007, Sunder Lal and Tej Singh gave an ID-based multi-proxy multi-signcryption scheme. By analysis, we discover that Sunder Lal and Tej Singh's scheme wrongly used two types of undefined bilinear pairing calculations, which caused that the calculation of Lal and Tej Singh's scheme is unfeasible. Against the error, we give an improved scheme. To avoid of using these undefined calculations and make it feasible, the improved scheme takes use of a more Hash function. At last, the security of the improved scheme is analyzed.