Construction of Threshold Public-Key Encryptions through Tag-Based Encryptions

Arita, Seiko; Tsurudome, Koji

doi:10.1007/978-3-642-01957-9_12

Cited by 12 publications

(13 citation statements)

References 8 publications

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“…In distributed tag-based encryption [4,15], the (tag-based) ciphertexts can only be decrypted if all n decryption servers compute their decryption shares correctly. In the threshold variant, at least κ out of n decryption servers must compute their decryption shares correctly for the decryption to succeed.…”

Section: Robust Non-interactive Distributed/threshold Tag-based Encrymentioning

confidence: 99%

Stronger Security Notions for Decentralized Traceable Attribute-Based Signatures and More Efficient Constructions

Ghadafi

2015

Lecture Notes in Computer Science

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Abstract. In this work, we revisit the notion of Decentralized Traceable Attribute-Based Signatures (DTABS) introduced by El Kaafarani et al. (CT-RSA 2014) and improve the state-of-the-art in three dimensions: Firstly, we provide a new stronger security model which circumvents some shortcomings in existing models. Our model minimizes the trust placed in attribute authorities and hence provides, among other things, a stronger definition for non-frameability. In addition, unlike previous models, our model captures the notion of tracing soundness which is important for many applications of the primitive, and which ensures that even if all parties in the system are fully corrupt, no one but the actual signer can claim authorship of the signature. Secondly, we provide a generic construction that is secure w.r.t. our strong security model and show two example instantiations in the standard model which are more efficient than existing constructions (secure under weaker security definitions). Finally, unlike existing constructions, we dispense with the need for the expensive zero-knowledge proofs required for proving tracing correctness by the tracing authority. As a result, tracing a signature in our constructions is significantly more efficient than existing constructions, both in terms of the size of the tracing proof and the computational cost required to generate and verify it. For instance, verifying tracing correctness in our constructions requires only 4 pairings compared to 34 pairings in the most efficient existing construction.

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Section: Robust Non-interactive Distributed/threshold Tag-based Encrymentioning

confidence: 99%

Stronger Security Notions for Decentralized Traceable Attribute-Based Signatures and More Efficient Constructions

Ghadafi

2015

Lecture Notes in Computer Science

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“…We show an efficient transformation from robust TPKC to PKENO. When applied to the schemes in [SG98,AT09], the conversion provides new practical PKENO schemes based on the Decisional Diffie-Hellman (in the random oracle model) and the Decisional Linear assumptions, respectively.…”

Section: Our Contributionsmentioning

confidence: 99%

“…It turns out that for concrete TPKC constructions, such as the Shoup and Gennaro [SG98] and the Arita and Tsurudome [AT09] schemes, it is possible to set n = t = 1 for improved efficiency. For instance, the consistency check between PK and (VK 1 , .…”

Section: Robust Tpkc Implies Pkenomentioning

confidence: 99%

“…Recently, Arita and Tsurudome [AT09] described an efficient way to thresholdize the decryption algorithm of Kiltz's tag-based encryption scheme [Kil06] using bilinear maps to achieve robustness. Their scheme readily yields another PKENO with strong soundness since it also provides decryption consistency in the strongest sense.…”

Section: Pkeno Based On the Decision Linear Assumptionmentioning

confidence: 99%

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Public-Key Encryption with Non-Interactive Opening: New Constructions and Stronger Definitions

Galindo

Libert

Fischlin

et al. 2010

Progress in Cryptology – AFRICACRYPT 2010

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Abstract. Public-key encryption schemes with non-interactive opening (PKENO) allow a receiver to non-interactively convince third parties that a ciphertext decrypts to a given plaintext or, alternatively, that such a ciphertext is invalid. Two practical generic constructions for PKENO have been proposed so far, starting from either identity-based encryption or public-key encryption with witness-recovering decryption (PKEWR). We show that the known transformation from PKEWR to PKENO fails to provide chosen-ciphertext security; only the transformation from identity-based encryption remains thus valid. Next, we prove that PKENO can be built out of robust non-interactive threshold publickey cryptosystems, a primitive seemingly weaker than identity-based encryption. Using the new transformation, we construct two efficient PKENO schemes: one based on the Decisional Diffie-Hellman assumption (in the Random Oracle Model) and one based on the Decisional Linear assumption (in the standard model). Last but not least, we propose new applications of PKENO in protocol design. Motivated by these applications, we reconsider proof soundness for PKENO and put forward new definitions that are stronger than those considered so far. We give a taxonomy of all definitions and demonstrate them to be satisfiable.

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“…the validity of the decryption shares as well as the ciphertext is publicly verifiable. The scheme works in the efficient Type-III bilinear groups setting and yields short ciphertexts which are much shorther than those of the original Kiltz's tag-based encryption scheme [42] and its threshold variant of [6]. By combining our scheme with a strongly unforgeable one-time signature scheme as per the transformation in [42], we obtain an efficient fully secure IND-CCA distributed/threshold encryption scheme, which is useful for many applications beyond the scope of this paper.…”

Section: Introductionmentioning

confidence: 96%

Efficient Distributed Tag-Based Encryption and Its Application to Group Signatures with Efficient Distributed Traceability

Ghadafi

2015

Progress in Cryptology - LATINCRYPT 2014

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Abstract. In this work, we first formalize the notion of dynamic group signatures with distributed traceability, where the capability to trace signatures is distributed among n managers without requiring any interaction. This ensures that only the participation of all tracing managers permits tracing a signature, which reduces the trust placed in a single tracing manager. The threshold variant follows easily from our definitions and constructions. Our model offers strong security requirements. Our second contribution is a generic construction for the notion which has a concurrent join protocol, meets strong security requirements, and offers efficient traceability, i.e. without requiring tracing managers to produce expensive zero-knowledge proofs for tracing correctness. To dispense with the expensive zero-knowledge proofs required in the tracing, we deploy a distributed tag-based encryption with public verifiability. Finally, we provide some concrete instantiations, which, to the best of our knowledge, are the first efficient provably secure realizations in the standard model simultaneously offering all the aforementioned properties. To realize our constructions efficiently, we construct an efficient distributed (and threshold) tag-based encryption scheme that works in the efficient Type-III asymmetric bilinear groups. Our distributed tag-based encryption scheme yields short ciphertexts (only 1280 bits at 128-bit security), and is secure under an existing variant of the standard decisional linear assumption. Our tag-based encryption scheme is of independent interest and is useful for many applications beyond the scope of this paper. As a special case of our distributed tag-based encryption scheme, we get an efficient tag-based encryption scheme in Type-III asymmetric bilinear groups that is secure in the standard model.

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Construction of Threshold Public-Key Encryptions through Tag-Based Encryptions

Cited by 12 publications

References 8 publications

Stronger Security Notions for Decentralized Traceable Attribute-Based Signatures and More Efficient Constructions

Stronger Security Notions for Decentralized Traceable Attribute-Based Signatures and More Efficient Constructions

Public-Key Encryption with Non-Interactive Opening: New Constructions and Stronger Definitions

Efficient Distributed Tag-Based Encryption and Its Application to Group Signatures with Efficient Distributed Traceability

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