Shanshan Duan

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The concept of certificateless public key cryptography (CL-PKC) was introduced by Al-Riyami and Paterson. Such a cryptosystem does not suffer from the key escrow problem while avoiding the onerous management of certificates. In this paper, we present the first certificateless undeniable signature scheme. We consider two different types of adversaries and(More)
In this paper, we first construct a security model for delegation-by-warrant ID-based proxy signcryption schemes and formalize notions of security for them. To the best of our knowledge, no related work has been done. Then we present such a scheme based on the bilinear pairings, and show that it is provably secure in the random oracle model. Specifically,(More)
We initiate the formal study on authenticated key exchange (AKE) under bad randomness. This could happen when (1) an adversary compromises the randomness source and hence directly controls the randomness of each AKE session; and (2) the randomness repeats in different AKE sessions due to reset attacks. We construct two formal security models, Reset-1 and(More)
Key insulation (KI) and Intrusion resilience (IR) are methods to protect a user's key against exposure by utilizing periodic communications with an auxiliary helper. But existing work assumes a secure channel between user and helper. If we want to realize KI or IR in practice we must realize this secure channel. This paper looks at the question of how to do(More)
We introduce Partial Signatures, where a signer, given a message, can compute a " stub " which preserves her anonymity, yet later she, but nobody else, can complete the stub to a full and verifiable signature under her public key. We provide a formal definition requiring three properties, namely anonymity, unambiguity and unforgeability. We provide schemes(More)
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