Time-Specific Encryption

Paterson, Kenneth G.; Quaglia, Elizabeth A.

doi:10.1007/978-3-642-15317-4_1

Cited by 57 publications

(22 citation statements)

References 23 publications

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“…In particular, we neither need trusted third parties, nor have a considerable computational overhead for decryption. Time-lock puzzles and proofs of (sequential) work [24,29,34,35,58,59,65,66] are computational problems that can not be solved without running a computer continuously for a certain time. In a sense, our computational reference clocks can be seen as algorithms that continuously and publicly solve publicly verifiable [59] instances of an infinite sequence of time-lock puzzles.…”

Section: Related Work and Further Applications Of Time-lock Encryptionmentioning

confidence: 99%

How to build time-lock encryption

Liu

Jager

Kakvi

et al. 2018

Des. Codes Cryptogr.

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Time-lock encryption is a method to encrypt a message such that it can only be decrypted after a certain deadline has passed. We propose a novel time-lock encryption scheme, whose main advantage over prior constructions is that even receivers with relatively weak computational resources should immediately be able to decrypt after the deadline, without any interaction with the sender, other receivers, or a trusted third party. We build our time-lock encryption on top of the new concept of computational reference clocks and an extractable witness encryption scheme. We explain how to construct a computational reference clock based on Bitcoin. We show how to achieve constant level of multilinearity for witness encryption by using SNARKs. We propose a new construction of a witness encryption scheme which is of independent interest: our scheme, based on Subset-Sum, achieves extractable security without relying on obfuscation. The scheme employs multilinear maps of arbitrary order and is independent of the implementations of multilinear maps.

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Section: Related Work and Further Applications Of Time-lock Encryptionmentioning

confidence: 99%

How to build time-lock encryption

Liu

Jager

Kakvi

et al. 2018

Des. Codes Cryptogr.

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“…Even though Bethencourt et al [5] gave a bitwise-matching method to implement integer comparison based on CP-ABE scheme, this method unfortunately is not efficient enough for practical applications. In addition, Time-specific encryption (TSE) [15] and multi-dimensional range queries over encrypted data (MRQED) [18] are, in essence, constructed on the similar bitwise approach with BSW's CP-ABE scheme, which makes use of a policy tree (consists of 0/1 branches) on equal matching to realize the integer comparison.…”

Section: Related Workmentioning

confidence: 99%

Comparison-based encryption for fine-grained access control in clouds

Zhu

Ahn

et al. 2012

Proceedings of the Second ACM Conference on Data and Application Security and Privacy

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Access control is one of the most important security mechanisms in cloud computing. However, there has been little work that explores various comparison-based constraints for regulating data access in clouds. In this paper, we present an innovative comparison-based encryption scheme to facilitate fine-grained access control in cloud computing. By means of forward/backward derivation functions, we introduce comparison relation into attribute-based encryption to implement various range constraints on integer attributes, such as temporal and level attributes. Then, we present a new cryptosystem with dual decryption to reduce computational overheads on cloud clients, where the majority of decryption operations are executed in cloud servers. We also prove the security strength of our proposed scheme, and our experiment results demonstrate the efficiency of our methodology.

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“…Being an encryption scheme with enhanced time control mechanism, SUE can be applied in various other cryptographic primitives such as time-release encryption [14] and key-insulated encryption [6] to provide better security guarantees.…”

Section: Introductionmentioning

confidence: 99%

Fully Secure Self-Updatable Encryption in Prime Order Bilinear Groups

Datta

Dutta

Mukhopadhyay

2014

Lecture Notes in Computer Science

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Abstract. In CRYPTO 2012, Sahai et al. raised the concern that in a cloud control system revocation of past keys should also be accompanied by updation of previously generated ciphertexts in order to prevent unread ciphertexts from being read by revoked users. Self-updatable encryption (SUE), introduced by Lee et al. in ASIACRYPT 2013, is a newly developed cryptographic primitive that realizes ciphertext update as an inbuilt functionality and thus improves the efficiency of key revocation and time evolution in cloud management. In SUE, a user can decrypt a ciphertext associated with a specific time if and only if the user possesses a private key corresponding to either the same time as that of the ciphertext or some future time. Furthermore, a ciphertext attached to a certain time can be updated to a new one attached to a future time using only public information. The SUE schemes available in the literature are either (a) fully secure but developed in a composite order bilinear group setting under highly non-standard assumptions or (b) designed in prime order bilinear groups but only selectively secure. This paper presents the first fully secure SUE scheme in prime order bilinear groups under standard assumptions, namely, the Decisional Linear and the Decisional Bilinear Diffie-Hellman assumptions. As pointed out by Freeman (EUROCRYPT 2010) and Lewko (EUROCRYPT 2012), the communication and storage, as well as, computational efficiency of prime order bilinear groups are much higher compared to that of composite order bilinear groups with an equivalent level of security. Consequently, our SUE scheme is highly cost-effective than the existing fully secure SUE.

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Time-Specific Encryption

Cited by 57 publications

References 23 publications

How to build time-lock encryption

How to build time-lock encryption

Comparison-based encryption for fine-grained access control in clouds

Fully Secure Self-Updatable Encryption in Prime Order Bilinear Groups

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