Threshold Proxy Digital Signature And Its Extension Study

Digital signature is one of the important way to protect information security.Since digital signature was introduced, it have been extensively studied. Thresholdproxy signature as a special kind of digital signature, because of its combines thresh-old characteristic and proxy characteristic, plays an important role in E-commerceand enterprise management.In this thesis, we research model and security of threshold proxy signature,threshold proxy threshold signature and hybrid threshold proxy signature. whichconsists of the following aspects:1. We point out the weakness of Lu et al.'s threshold proxy signature scheme,and improve it by putting (t,n) - V SS technology in the proxy key generate phaseto overcome Lu scheme's weakness.2.We propose secure model of threshold proxy threshold signature. Based on theabove threshold proxy signature, we extend it to a secure threshold proxy thresholdsignature scheme.3. Based on the Wang's hybrid proxy multi-signature scheme, we expand itsapplication environment and define the model and notion of hybrid threshold proxysignature, and construct a secure hybrid threshold proxy signature scheme.