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145
Attributebased encryption for finegrained access control of encrypted data
 In Proc. of ACMCCS’06
, 2006
"... As more sensitive data is shared and stored by thirdparty sites on the Internet, there will be a need to encrypt data stored at these sites. One drawback of encrypting data, is that it can be selectively shared only at a coarsegrained level (i.e., giving another party your private key). We develop ..."
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Cited by 481 (23 self)
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As more sensitive data is shared and stored by thirdparty sites on the Internet, there will be a need to encrypt data stored at these sites. One drawback of encrypting data, is that it can be selectively shared only at a coarsegrained level (i.e., giving another party your private key). We develop a new cryptosystem for finegrained sharing of encrypted data that we call KeyPolicy AttributeBased Encryption (KPABE). In our cryptosystem, ciphertexts are labeled with sets of attributes and private keys are associated with access structures that control which ciphertexts a user is able to decrypt. We demonstrate the applicability of our construction to sharing of auditlog information and broadcast encryption. Our construction supports delegation of private keys which subsumes Hierarchical IdentityBased Encryption (HIBE). E.3 [Data En
Short Signatures without Random Oracles
, 2004
"... We describe a short signature scheme which is existentially unforgeable under a chosen message attack without using random oracles. The security of our scheme depends on a new complexity assumption we call the Strong Di#eHellman assumption. This assumption has similar properties to the Strong RS ..."
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Cited by 387 (13 self)
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We describe a short signature scheme which is existentially unforgeable under a chosen message attack without using random oracles. The security of our scheme depends on a new complexity assumption we call the Strong Di#eHellman assumption. This assumption has similar properties to the Strong RSA assumption, hence the name. Strong RSA was previously used to construct signature schemes without random oracles. However, signatures generated by our scheme are much shorter and simpler than signatures from schemes based on Strong RSA.
Fuzzy identitybased encryption
 In EUROCRYPT
, 2005
"... We introduce a new type of IdentityBased Encryption (IBE) scheme that we call Fuzzy IdentityBased Encryption. In Fuzzy IBE we view an identity as set of descriptive attributes. A Fuzzy IBE scheme allows for a private key for an identity, ω, to decrypt a ciphertext encrypted with an identity, ω ′ , ..."
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Cited by 354 (20 self)
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We introduce a new type of IdentityBased Encryption (IBE) scheme that we call Fuzzy IdentityBased Encryption. In Fuzzy IBE we view an identity as set of descriptive attributes. A Fuzzy IBE scheme allows for a private key for an identity, ω, to decrypt a ciphertext encrypted with an identity, ω ′ , if and only if the identities ω and ω ′ are close to each other as measured by the “set overlap ” distance metric. A Fuzzy IBE scheme can be applied to enable encryption using biometric inputs as identities; the errortolerance property of a Fuzzy IBE scheme is precisely what allows for the use of biometric identities, which inherently will have some noise each time they are sampled. Additionally, we show that FuzzyIBE can be used for a type of application that we term “attributebased encryption”. In this paper we present two constructions of Fuzzy IBE schemes. Our constructions can be viewed as an IdentityBased Encryption of a message under several attributes that compose a (fuzzy) identity. Our IBE schemes are both errortolerant and secure against collusion attacks. Additionally, our basic construction does not use random oracles. We prove the security of our schemes under the SelectiveID security model. 1
Efficient identitybased encryption without random oracles
, 2005
"... We present the first efficient IdentityBased Encryption (IBE) scheme that is fully secure without random oracles. We first present our IBE construction and reduce the security of our scheme to the decisional Bilinear DiffieHellman (BDH) problem. Additionally, we show that our techniques can be use ..."
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Cited by 339 (18 self)
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We present the first efficient IdentityBased Encryption (IBE) scheme that is fully secure without random oracles. We first present our IBE construction and reduce the security of our scheme to the decisional Bilinear DiffieHellman (BDH) problem. Additionally, we show that our techniques can be used to build a new signature scheme that is secure under the computational DiffieHellman assumption without random oracles. 1
ChosenCiphertext Security from IdentityBased Encryption. Adv
 in Cryptology — Eurocrypt 2004, LNCS
, 2004
"... We propose simple and efficient CCAsecure publickey encryption schemes (i.e., schemes secure against adaptive chosenciphertext attacks) based on any identitybased encryption (IBE) scheme. Our constructions have ramifications of both theoretical and practical interest. First, our schemes give a n ..."
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Cited by 279 (14 self)
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We propose simple and efficient CCAsecure publickey encryption schemes (i.e., schemes secure against adaptive chosenciphertext attacks) based on any identitybased encryption (IBE) scheme. Our constructions have ramifications of both theoretical and practical interest. First, our schemes give a new paradigm for achieving CCAsecurity; this paradigm avoids “proofs of wellformedness ” that have been shown to underlie previous constructions. Second, instantiating our construction using known IBE constructions we obtain CCAsecure encryption schemes whose performance is competitive with the most efficient CCAsecure schemes to date. Our techniques extend naturally to give an efficient method for securing also IBE schemes (even hierarchical ones) against adaptive chosenciphertext attacks. Coupled with previous work, this gives the first efficient constructions of CCAsecure IBE schemes. 1
Fully Secure Functional Encryption: AttributeBased Encryption and (Hierarchical) Inner Product Encryption
"... In this paper, we present two fully secure functional encryption schemes. Our first result is a fully secure attributebased encryption (ABE) scheme. Previous constructions of ABE were only proven to be selectively secure. We achieve full security by adapting the dual system encryption methodology r ..."
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Cited by 139 (21 self)
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In this paper, we present two fully secure functional encryption schemes. Our first result is a fully secure attributebased encryption (ABE) scheme. Previous constructions of ABE were only proven to be selectively secure. We achieve full security by adapting the dual system encryption methodology recently introduced by Waters and previously leveraged to obtain fully secure IBE and HIBE systems. The primary challenge in applying dual system encryption to ABE is the richer structure of keys and ciphertexts. In an IBE or HIBE system, keys and ciphertexts are both associated with the same type of simple object: identities. In an ABE system, keys and ciphertexts are associated with more complex objects: attributes and access formulas. We use a novel informationtheoretic argument to adapt the dual system encryption methodology to the more complicated structure of ABE systems. We construct our system in composite order bilinear groups, where the order is a product of three primes. We prove the security of our system from three static assumptions. Our ABE scheme supports arbitrary monotone access formulas. Our second result is a fully secure (attributehiding) predicate encryption (PE) scheme
Attributebased encryption with nonmonotonic access structures
 In ACM CCCS
, 2007
"... We construct an AttributeBased Encryption (ABE) scheme that allows a user’s private key to be expressed in terms of any access formula over attributes. Previous ABE schemes were limited to expressing only monotonic access structures. We provide a proof of security for our scheme based on the Decisi ..."
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Cited by 119 (5 self)
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We construct an AttributeBased Encryption (ABE) scheme that allows a user’s private key to be expressed in terms of any access formula over attributes. Previous ABE schemes were limited to expressing only monotonic access structures. We provide a proof of security for our scheme based on the Decisional Bilinear DiffieHellman (BDH) assumption. Furthermore, the performance of our new scheme compares favorably with existing, lessexpressive schemes. Categories and Subject Descriptors: E.3 [Data Encryption]: Public key cryptosystems. General Terms: Security.
Fully secure functional encryption with general relations from the decisional linear assumption
 In CRYPTO
, 2010
"... This paper presents a fully secure functional encryption scheme for a wide class of relations, that are specified by nonmonotone access structures combined with innerproduct relations. The security is proven under a standard assumption, the decisional linear (DLIN) assumption, in the standard mode ..."
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Cited by 78 (0 self)
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This paper presents a fully secure functional encryption scheme for a wide class of relations, that are specified by nonmonotone access structures combined with innerproduct relations. The security is proven under a standard assumption, the decisional linear (DLIN) assumption, in the standard model. The proposed functional encryption scheme covers, as special cases, (1) keypolicy, ciphertextpolicy and unifiedpolicy (of key and ciphertext policies) attributebased encryption with nonmonotone access structures, and (2) (hierarchical) predicate encryption with innerproduct relations and functional encryption with nonzero
A verifiable random function with short proofs and keys
 PKC 2005, LNCS
, 2005
"... Abstract. We give a simple and efficient construction of a verifiable random function (VRF) on bilinear groups. Our construction is direct. In contrast to prior VRF constructions [14, 15], it avoids using an inefficient GoldreichLevin transformation, thereby saving several factors in security. Our ..."
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Cited by 75 (3 self)
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Abstract. We give a simple and efficient construction of a verifiable random function (VRF) on bilinear groups. Our construction is direct. In contrast to prior VRF constructions [14, 15], it avoids using an inefficient GoldreichLevin transformation, thereby saving several factors in security. Our proofs of security are based on a decisional bilinear DiffieHellman inversion assumption, which seems reasonable given current state of knowledge. For small message spaces, our VRF’s proofs and keys have constant size. By utilizing a collisionresistant hash function, our VRF can also be used with arbitrary message spaces. We show that our scheme can be instantiated with an elliptic group of very reasonable size. Furthermore, it can be made distributed and proactive. 1
New Techniques for Dual System Encryption and Fully Secure HIBE with Short Ciphertexts
"... We construct a fully secure HIBE scheme with short ciphertexts. The previous construction of Boneh, Boyen, and Goh was only proven to be secure in the selective model, under a nonstatic assumption which depended on the depth of the hierarchy. To obtain full security, we apply the dual system encryp ..."
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Cited by 74 (13 self)
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We construct a fully secure HIBE scheme with short ciphertexts. The previous construction of Boneh, Boyen, and Goh was only proven to be secure in the selective model, under a nonstatic assumption which depended on the depth of the hierarchy. To obtain full security, we apply the dual system encryption concept recently introduced by Waters. A straightforward application of this technique is insufficient to achieve short ciphertexts, since the original instantiation of the technique includes tags that do not compress. To overcome this challenge, we design a new method for realizing dual system encryption. We provide a system in composite order groups (of three primes) and prove the security of our scheme under three static assumptions.