Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

HRA-Secure Proxy Re-encryption with Re-encryption Simulatability under Lwe in Standard Model

Bimei Wang, Lin Hou, Lisha Yao, Feixiang Zhao, Jian Weng

Published Nov 28, 2023• 0 citations
Publisher

Abstract

Proxy re-encryption (PRE) is a momentous and widely used cryptographic technique. It enables a proxy to forward ciphertext without the need of decryption. PRE has received significant interest in applications like cloud computing, blockchain, and the Internet of Things. Despite its wide range of uses, PRE has also been subject to new security and privacy regulations. In PKC’19, Cohen $et~al.$~first drew attention to the weakness in PRE's security against chosen-plaintext attacks (CPA) and put up a more stringent security concept known as security against honest re-encryption attacks (HRA). Notably, Cohen provides a beneficial conclusion as well. It is proveded that PRE schemes with re-encryption simulatability property can be elevated from CPA to HRA security. It is also proved that CPA-secure PRE schemes with re-encryption simulatability property can be directly elevated to those satisfying HRA security. However, those PRE schemes with re-encryption simulatability are almost always based on pairings. In this study, to the best of our knowledge, we directly construct HRA-secure PRE with re-encryption simulatability for the first time based on the learning with errors (LWE) assumption, which was widely believed to be quantum-resistant. Based on the re-encryption key generation algorithm and the re-encryption algorithm construction method of the above scheme, we can modify attribute-based conditional proxy re-encryption (AB-CPRE) as well as the corresponding attribute-based proxy re-encryption (AB-PRE) algorithm to make them have re-encryption simulatability properties. Finally, by using this property, We boost the security of AB-CPRE scheme of ESORICS'21 from CPA to HRA and simplify the HRA-security proof for the AB-PRE of ESORICS'21.

DOI
10.20944/preprints202311.1769.v1

Related papers

Improved AB-CPREs with HRA Security

Yu Zhang, Yang Wang, Mingqiang Wang

Attribute-based conditional proxy re-encryption (AB-CPRE) schemes offer flexible controls over delegations of decryption rights, and offer an efficient solution for enforcing access control on outsourced encrypted datum. Recently, Liang et al. proposed the first lattice-based AB-CPREs with selective attribute security against chosen-plaintext attacks (CPA) in ESORICS 2021. In this paper, we first show how to construct a CPA secure AB-CPRE scheme which is suitable for circuits in NC $^{1}$ with polynomially bounded parameters. By contrast, schemes proposed by Liang et al. are only suitable for circuits in NC $^{0}$ with similar parameters. We then show how to convert our CPA secure AB-CPREs to be secure against honest re-encryption attacks (HRA) under a more reasonable definition. We could show that the CPA security and the HRA security of our schemes are based on standard LWE assumptions for suitable parameters in the standard model.

International Conference on Data Security and Privacy Protection (DSPP)•Oct 16, 2023•2 citations

Lattice-Based Key Private Pres with HRA Security and Pcs Security

Yang Wang, Yanmin Zhao, Mingqiang Wang

Proxy re-encryption (PRE) schemes, which nicely solve the problem of delegating decryption rights, enable a semi-trusted proxy to transform a ciphertext encrypted under one key into a ciphertext of the same message under another arbitrary key. Cohen first pointed out the insufficiency of the security under chosen-plaintext attacks (CPA) of PREs in PKC 2019, and proposed a strictly stronger security notion, named security under honest re-encryption attacks (HRA), of PREs. Surprisingly, a few PREs satisfy the stronger HRA security and almost all of them are paring-based till now. To the best of our knowledge, we present the first direct construction of HRA secure single-hop PREs based on standard LWE problems with comparably small and polynomially-bounded parameters in this paper. Combing known reductions, the HRA security of our PREs could also be guaranteed by the worst-case basic lattice problems (e.g. SIVPγ with γ=Õ(n3.5)). Our single-hop PRE schemes are key-private, which means that the implicit identities of a re-encryption key will not be revealed even in the case of a proxy colluding with some corrupted users. Meanwhile, our single-hop PRE schemes are also post-compromise (PCS) secure, ensuring that a re-encrypted ciphertext remains confidential even when the past key, potential old ciphertexts and the re-encryption key have been exposed. Some discussions about key-privacy of multi-hop PREs are also proposed, which indicates that several constructions of multi-hop PREs do not satisfy their key-privacy definitions.

Computer Standards & Interfaces•Jan 1, 2022•4 citations

Toward Proxy Re-encryption From Learning with Errors in the Exponent

Zengpeng Li, Chunguang Ma, Ding Wang +3 more

Proxy re-encryption (PRE) is an important cryptographic primitive used for private information sharing. However, the recent advance in quantum computer has potentially crippled its security, as the traditional decisional Diffie-Hellman (DDH)-based PRE is venerable to the quantum attack. Thus, learning with errors (LWE)-based PRE schemes, as a kind of latticebased construction with the inherent quantum-resistant property, has attracted special research interest. Unfortunately, the main drawback of lattice-based public key encryption scheme is noise management after multiplication evaluation. Many cryptographers have been devoted to controlling the expansion of noise. In this line of work, Dagdelen-Gajek-G̈opfert (DGG) put forth the notion of learning with errors in the exponent (LWEE) which is based on lattice and group-theoretic assumption, meanwhile demonstrated a paradigm for constructing efficient quantum resistance public key schemes. In this paper, on top of DGG, we construct a single-bit, single-hop and unidirectional LWEE- based PRE scheme with indistinguishable chosen plaintext attack (IND-CPA) security. To the best of our knowledge, our scheme is the first LWEE-based PRE scheme.

IEEE International Conference on Trust, Security and Privacy in Computing and Communications (TrustCom)•Aug 1, 2017•1 citation

Chosen-Ciphertext Secure Proxy Re-Encryption for Bounded Linear Functions

Fucai Luo, Haiyan Wang, Xingfu Yan +1 more

Proxy re-encryption (PRE) allows a proxy to use the reencryption keys to convert ciphertexts encrypted under the delegators' public keys into ones that can be decrypted using the delegatees' secret keys, without revealing the underlying plaintext. However, PRE is limited to an all-or-nothing re-encryption, that is, the delegatee can either decrypt the re-encrypted ciphertext to obtain the whole message, or it learns nothing about the underlying message. To address this limitation, Zhou et al. (Asiacrypt 2023) proposed a new variant of PRE called fine-grained PRE (FPRE). FPRE extends PRE to support fine-grained re-encryption, allowing the proxy to convert any ciphertext encrypting a message m to a new ciphertext encrypting f (m) with a fine-grained re-encryption key for any function f. This enables the delegator to flexibly control the sharing of messages by specifying functions. Unfortunately, their scheme achieves only CPA security and requires a common random/reference string (CRS) during key generation. This requirement may weaken the syntax of (F)PRE, which allows users to independently generate their own keys. In this paper, we propose a new FPRE for bounded linear functions that we prove is CCA1 secure and does not require a CRS, based on the Learning with Errors (LWE) assumption. When the linear function is set to be the identity function, our construction immediately yields the first PRE scheme without a CRS, with CCA1 security under adaptive corruptions in the standard model. The main technique behind our construction is the design of a deterministic preimage computation algorithm for the decryption oracle in the security proof. To demonstrate the broader applicability of our proposed algorithm beyond the context of (F)PRE, we use it to prove the selective-identity CCA1 security of Agrawal et al.'s (Eurocrypt 2010) identity-based encryption (IBE) scheme, which was previously only known to be selective-identity CPA secure.

•Dec 5, 2024•0 citations

Identity Based Proxy Re-encryption Scheme under LWE

Wei Yin, Qiaoyan Wen, Wenmin Li +2 more

The proxy re-encryption allows an intermediate proxy to convert a ciphertext for Alice into a ciphertext for Bob without seeing the original message and leaking out relevant information.Unlike many prior identity based proxy re-encryption schemes which are based on the number theoretic assumptions such as large integer factorization and discrete logarithm problem.In this paper, we first propose a novel identity based proxy re-encryption scheme which is based on the hardness of standard Learning With Error(LWE) problem and is CPA secure in the standard model.This scheme can be reduced to the worst-case lattice hard problem that is able to resist attacks from quantum algorithm.The key step in our construction is that the challenger how to answer the private query under a known trapdoor matrix.Our scheme enjoys properties of the non-interactivity, unidirectionality, anonymous and so on.In this paper, we utilize primitives include G-trapdoor for lattice and sample algorithms to realize simple and efficient re-encryption.

KSII Transactions on Internet and Information Systems•Dec 31, 2017•6 citations

Identity-Based Proxy Re-Encryption Based on LWE with Short Parameters

Keyuan Zhang, Yuan Liu, Licheng Wang +1 more

Proxy re-encryption (PRE) can guarantee the security of data sharing in the cloud making it important in ciphertext sharing in the cloud computing environment. Plenty of the current PRE algorithms based on the learning with errors (LWE) problem are constructed under the random oracle model or have problems such as long public parameter size, large ciphertext expansion rate, etc. We propose an identity-based PRE (IB-PRE) scheme using the LWE problem with short public parameters which can solve the mentioned challenges. Our scheme uses the blocking operation to decrease the public parameter size and a more useful trapdoor generation algorithm to reduce the trapdoor size. These two technologies improve the computational efficiency of the public key. We think that when we divide the identity id into 16 blocks, without much increase in computational overhead, the public key size can be reduced by 88.34%, and the scheme’s security level can remain unchanged. Our scheme achieves adaptive IND-ID-CPA security. It is unidirectional, collusion-resistant, and constructed under the standard model.

International Conference on Mobile Internet, Cloud Computing and Information Security (MICCIS)•Apr 1, 2023•1 citation
Proxy re-encryption (PRE) is a momentous and widely used cryptographic technique. It enables a proxy to forward ciphertext without the need of decryption. PRE has received significant interest in applications like cloud computing, blockchain, and the Internet of Things. Despite its wide range of uses, PRE has also been subject to new security and privacy regulations. In PKC’19, Cohen et al.et~al.et al.~first drew attention to the weakness in PRE's security against chosen-plaintext attacks (CPA) and put up a more stringent security concept known as security against honest re-encryption attacks (HRA). Notably, Cohen provides a beneficial conclusion as well. It is proveded that PRE schemes with re-encryption simulatability property can be elevated from CPA to HRA security. It is also proved that CPA-secure PRE schemes with re-encryption simulatability property can be directly elevated to those satisfying HRA security. However, those PRE schemes with re-encryption simulatability are almost always based on pairings. In this study, to the best of our knowledge, we directly construct HRA-secure PRE with re-encryption simulatability for the first time based on the learning with errors (LWE) assumption, which was widely believed to be quantum-resistant. Based on the re-encryption key generation algorithm and the re-encryption algorithm construction method of the above scheme, we can modify attribute-based conditional proxy re-encryption (AB-CPRE) as well as the corresponding attribute-based proxy re-encryption (AB-PRE) algorithm to make them have re-encryption simulatability properties. Finally, by using this property, We boost the security of AB-CPRE scheme of ESORICS'21 from CPA to HRA and simplify the HRA-security proof for the AB-PRE of ESORICS'21.
Attribute-based conditional proxy re-encryption (AB-CPRE) schemes offer flexible controls over delegations of decryption rights, and offer an efficient solution for enforcing access control on outsourced encrypted datum. Recently, Liang et al. proposed the first lattice-based AB-CPREs with selective attribute security against chosen-plaintext attacks (CPA) in ESORICS 2021. In this paper, we first show how to construct a CPA secure AB-CPRE scheme which is suitable for circuits in NC 1^{1}1 with polynomially bounded parameters. By contrast, schemes proposed by Liang et al. are only suitable for circuits in NC 0^{0}0 with similar parameters. We then show how to convert our CPA secure AB-CPREs to be secure against honest re-encryption attacks (HRA) under a more reasonable definition. We could show that the CPA security and the HRA security of our schemes are based on standard LWE assumptions for suitable parameters in the standard model.
Proxy re-encryption (PRE) schemes, which nicely solve the problem of delegating decryption rights, enable a semi-trusted proxy to transform a ciphertext encrypted under one key into a ciphertext of the same message under another arbitrary key. Cohen first pointed out the insufficiency of the security under chosen-plaintext attacks (CPA) of PREs in PKC 2019, and proposed a strictly stronger security notion, named security under honest re-encryption attacks (HRA), of PREs. Surprisingly, a few PREs satisfy the stronger HRA security and almost all of them are paring-based till now. To the best of our knowledge, we present the first direct construction of HRA secure single-hop PREs based on standard LWE problems with comparably small and polynomially-bounded parameters in this paper. Combing known reductions, the HRA security of our PREs could also be guaranteed by the worst-case basic lattice problems (e.g. SIVPγ with γ=Õ(n3.5)). Our single-hop PRE schemes are key-private, which means that the implicit identities of a re-encryption key will not be revealed even in the case of a proxy colluding with some corrupted users. Meanwhile, our single-hop PRE schemes are also post-compromise (PCS) secure, ensuring that a re-encrypted ciphertext remains confidential even when the past key, potential old ciphertexts and the re-encryption key have been exposed. Some discussions about key-privacy of multi-hop PREs are also proposed, which indicates that several constructions of multi-hop PREs do not satisfy their key-privacy definitions.
Proxy re-encryption (PRE) is an important cryptographic primitive used for private information sharing. However, the recent advance in quantum computer has potentially crippled its security, as the traditional decisional Diffie-Hellman (DDH)-based PRE is venerable to the quantum attack. Thus, learning with errors (LWE)-based PRE schemes, as a kind of latticebased construction with the inherent quantum-resistant property, has attracted special research interest. Unfortunately, the main drawback of lattice-based public key encryption scheme is noise management after multiplication evaluation. Many cryptographers have been devoted to controlling the expansion of noise. In this line of work, Dagdelen-Gajek-G̈opfert (DGG) put forth the notion of learning with errors in the exponent (LWEE) which is based on lattice and group-theoretic assumption, meanwhile demonstrated a paradigm for constructing efficient quantum resistance public key schemes. In this paper, on top of DGG, we construct a single-bit, single-hop and unidirectional LWEE- based PRE scheme with indistinguishable chosen plaintext attack (IND-CPA) security. To the best of our knowledge, our scheme is the first LWEE-based PRE scheme.
Proxy re-encryption (PRE) allows a proxy to use the reencryption keys to convert ciphertexts encrypted under the delegators' public keys into ones that can be decrypted using the delegatees' secret keys, without revealing the underlying plaintext. However, PRE is limited to an all-or-nothing re-encryption, that is, the delegatee can either decrypt the re-encrypted ciphertext to obtain the whole message, or it learns nothing about the underlying message. To address this limitation, Zhou et al. (Asiacrypt 2023) proposed a new variant of PRE called fine-grained PRE (FPRE). FPRE extends PRE to support fine-grained re-encryption, allowing the proxy to convert any ciphertext encrypting a message m to a new ciphertext encrypting f (m) with a fine-grained re-encryption key for any function f. This enables the delegator to flexibly control the sharing of messages by specifying functions. Unfortunately, their scheme achieves only CPA security and requires a common random/reference string (CRS) during key generation. This requirement may weaken the syntax of (F)PRE, which allows users to independently generate their own keys. In this paper, we propose a new FPRE for bounded linear functions that we prove is CCA1 secure and does not require a CRS, based on the Learning with Errors (LWE) assumption. When the linear function is set to be the identity function, our construction immediately yields the first PRE scheme without a CRS, with CCA1 security under adaptive corruptions in the standard model. The main technique behind our construction is the design of a deterministic preimage computation algorithm for the decryption oracle in the security proof. To demonstrate the broader applicability of our proposed algorithm beyond the context of (F)PRE, we use it to prove the selective-identity CCA1 security of Agrawal et al.'s (Eurocrypt 2010) identity-based encryption (IBE) scheme, which was previously only known to be selective-identity CPA secure.
The proxy re-encryption allows an intermediate proxy to convert a ciphertext for Alice into a ciphertext for Bob without seeing the original message and leaking out relevant information.Unlike many prior identity based proxy re-encryption schemes which are based on the number theoretic assumptions such as large integer factorization and discrete logarithm problem.In this paper, we first propose a novel identity based proxy re-encryption scheme which is based on the hardness of standard Learning With Error(LWE) problem and is CPA secure in the standard model.This scheme can be reduced to the worst-case lattice hard problem that is able to resist attacks from quantum algorithm.The key step in our construction is that the challenger how to answer the private query under a known trapdoor matrix.Our scheme enjoys properties of the non-interactivity, unidirectionality, anonymous and so on.In this paper, we utilize primitives include G-trapdoor for lattice and sample algorithms to realize simple and efficient re-encryption.
Proxy re-encryption (PRE) can guarantee the security of data sharing in the cloud making it important in ciphertext sharing in the cloud computing environment. Plenty of the current PRE algorithms based on the learning with errors (LWE) problem are constructed under the random oracle model or have problems such as long public parameter size, large ciphertext expansion rate, etc. We propose an identity-based PRE (IB-PRE) scheme using the LWE problem with short public parameters which can solve the mentioned challenges. Our scheme uses the blocking operation to decrease the public parameter size and a more useful trapdoor generation algorithm to reduce the trapdoor size. These two technologies improve the computational efficiency of the public key. We think that when we divide the identity id into 16 blocks, without much increase in computational overhead, the public key size can be reduced by 88.34%, and the scheme’s security level can remain unchanged. Our scheme achieves adaptive IND-ID-CPA security. It is unidirectional, collusion-resistant, and constructed under the standard model.