Signatures With Additional Properties And Its Applications

Digital signatures become an important part of modern information society becausethey can solve many security problems, such as repudiation, forgery, tamper and imitation,etc., which are all important security requirements during the data transformation andstorage in the Internet. This dissertation investigate the technologies and applicationsof some digital signatures, include proxy signature, signature with message recovery andauthenticated encryption that with additional properties. The mainly obtained resultsare as follows:(1) A new type of proxy multi signature scheme is proposed. Proxy multi signature isa special kind of digital signature scheme, which can be used to solve the problemof signing on a document e?ciently by multiple signers.(2) The notion of anonymous proxy signature is introduced. We discuss the situationwhen proxy signers do not want any proxy signature receivers could determine theiractual identity from the proxy signature directly. And a new secure anonymousproxy signature with anonymity revocation is proposed.(3) Two forgery attacks are proposed on a proxy blind signature scheme proposed byTan et al. By successfully identifying the forgery attack, we show that their schemeis insecure. Furthermore, to improve Tan et al's scheme, we propose a new proxyblind signature scheme.(4) We find out that there are some similarities between group signatures and proxysignatures. A new group signature scheme with unlimited group size is proposedbased on the heuristic idea of proxy signature scheme with proxy signer's privacyprotection. In this group signature scheme the group manager plays the role of theoriginal signer, and the legal group members act as the proxy signers who delegatethe original signer's signing power.(5) A secure ID-based proxy signature scheme is proposed by using the knowledge of ID-based cryptography. Then based on the new ID-based proxy signature scheme, wepresent a new multi-proxy signature scheme and a new multi-proxy blind signaturescheme both are ID-based signatures.(6) Security analysis is been done to Zhang et al's ID-based ring signature scheme.Two new unconditionally anonymous proxy signature schemes are proposed, oneis a new proxy ring signature scheme, and another is unconditionally anonymousproxy signature scheme. Both of their anonymity cannot be traceable.(7) Two forgery attacks are proposed of a signature scheme with message recovery. Animproved authenticated encryption scheme with public verifiability is proposed. Fur-thermore, a model of authenticated encryption with public verifiability is presentedby using generalized ElGamal type signatures.