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| Nowadays, most proxy signature schemes are based on the difficulty of DLP (Discrete
Logarithm Problem) or ECDLP (Elliptical Curve Discrete Logarithm Problem). As
though many proxy signature schemes based on DLP or ECDLP have been proposed,
it makes us discouraged that some disadvantages can be found after a new or modified proxy signature scheme was designed after short time. How to solve the question? How to design secure and valid proxy signature schemes? How to prove them secure? Now, it is too difficult for us to prove one scheme secure, but if we can have some
principles to conform to when designing some proxy signature schemes based on DLP
or ECDLP, it will be helpful. It will be able to make scheme designers to make few
mistakes, that’s to say, by these principles, they can judge whether their schemes meet
these basic secure conditions or not. If designers don’t abide by these principles, it can easily be seen that their schemes are definitely insecure. It is all known that until now there are no such principles in the real life. The first principle is that the existent forms
of public parameters in proxy signatures in the proxy signature verification congruence make a key role on the security property of unforgeability; the second principle is that any public parameter in the proxy signature can’t lonely exist in the proxy signature verification congruence in the form of bases or exponents; the third principle is that any public parameter in the proxy signature should exist in the proxy signature verification equation in the form of not only exponents and bases, but also hashes. About these principles, they are described. In addition, some examples are made to make them clear. |
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| Keywords:Cryptography;Signature;Proxy signature;DLP;Principle |
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