Cryptanalysis and improvement of two signcryption schemes
Shaowu Zhang · Journal of Computer Applications · 2011
A certificateless signcryption scheme and a self-certified proxy signcryption scheme based on Discrete Logarithm Problem(DLP) were analyzed.It was pointed out that,in this certificateless signcryption scheme,besides the type Ⅰ attack proposed by Selvi et al.(SELVI S S D,VIVEK S S,RANGAN C P.Security weaknesses in two certificateless signcryption schemes.http://eprint.iacr.org/2010/092.pdf),there was another forgery attack which could successfully forge a signcryption passing the verification procedure and did not have public verifiability.In the self-certified proxy signcryption scheme based on Discrete Logarithm Problem(DLP),because of the existence of suspending-factor,any dishonest receiver could forge a signcryption passing the verification procedure.The attack methods and the improvement methods were presented.The experimental results prove that the proposed scheme is secure and effective,and it overcomes the flaw in the original schemes.