Cryptanalysis and Improvement of an Identity-Based Multi-Signcryption Scheme
Dingfeng Ye · Dianzi xuebao · 2011
Waters proposed an identity-based encryption and signature scheme in standard model.Then Paterson and Schuldt proposed an identity-based signature scheme based on Waters' IBE.Zhang and Xu proposed an identity-based multi-signcryption scheme that using the above schemes.However,we show that Zhang-Xu's scheme is insecure under randomizing private key attack.Furthermore,we propose an improved identity-based multi-signcryption scheme in standard model.In our scheme,we divide the private keys into two parts,one is for decryption,the other is for signature,and the private key used for signature cannot be randomized.Moreover,our scheme can resist insider leak attack.