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In this paper, we study the problem of secure integrating public key encryption with keyword search (PEKS) with public key data encryption (PKE). We argue the previous security model is not complete regarding keyword privacy and the previous constructions are secure only in the random oracle model. We solve these problems by first defining a new security(More)
We revisit the problem of finding small solutions to a collection of linear equations modulo an unknown divisor p for a known composite integer N. In Asiacrypt'08, Herrmann and May introduced a heuristic algorithm for this problem, and their algorithm has many interesting applications, such as factoring with known bits problem, fault attacks on RSA(More)
This paper shows that the standard security notion for identity based encryption schemes (IBE), that is IND-ID-CCA2, captures the essence of security for all IBE schemes. To achieve this intention, we first describe formal definitions of the notions of security for IBE, and then present the relations among OW, IND, SS and NM in IBE, along with rigorous(More)
In a practical system, a message is often encrypted more than once by different encryptions, here called multiple encryption, to enhance its security. Additionally, new features may be achieved by multiple en-crypting a message, such as the key-insulated cryptosystems and anonymous channels. Intuitively, a multiple encryption should remain " secure " ,(More)
In a seminal paper of identity based encryption (IBE), Boneh and Franklin [BF01] mentioned an interesting transform from an IBE scheme to a signature scheme, which was observed by Moni Naor. In this paper, we give formal security treatments for this transform and discover several implications and separations among security notions of IBE and transformed(More)
In a famous paper of Crypto'01, Boneh and Franklin proposed the first identity-based encryption scheme (IBE), around fifteen years after the concept was introduced by Shamir. Their scheme security (more precisely, the notion of resistance against an IND-ID-CCA attacker) relies in the random oracle model. However, the reduction is far from being tight, and(More)
The Fujisaki-Okamoto (FO) conversion is widely known to be able to generically convert a weak public key encryption scheme, say one-way against chosen plaintext attacks (OW-CPA), to a strong one, namely, indistinguishable against adaptive chosen ciphertext attacks (IND-CCA). It is not known that if the same holds for identity-based en-cryption (IBE)(More)