01379nas a2200193   4500000000100000000000100001008004100002260000900043653002800052653002200080653002000102653002500122100001700147700001900164245008000183300001200263490000700275520090300282       2003                            d  c200310acertification authority10aDigital Signature10aproxy signature10atime stamp authority1 aWei- Bin Lee1 aTzung-Her Chen00aConstructing a Proxy Signature Scheme Based on Existing Security Mechanisms  a250-2580 v123 a<p>A proxy signature allows a designated person, called a proxy signer, to sign a message on behalf of an original signer. Many proxy signature-related schemes have been proposed due to the fact that this type of scheme is very important. However, these new schemes always face security challenges. To minimize security challenges, the objective of the authors of this paper is to construct a proxy signature scheme that combines existing security mechanisms, rather than attempting to invent a new scheme. They believe that the proposed proxy signature scheme not only satisfies the essential properties mentioned in Mambo-Usuda-Okamoto’s proxy signature scheme but also has additional advantages, such as non-repudiation and prevention of delegation transfer. Furthermore, the fewer security challenges and easy implementation are direct benefits obtained from using the existing mechanisms</p>