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

IEEE Transactions on Information Theory

Comments on “Unidirectional Chosen-Ciphertext Secure Proxy Re-Encryption”

Jae Woo Seo, Dae Hyun Yum, Pil Joong Lee

Published Dec 27, 2012• 9 citations
Publisher

Abstract

Libert and Vergnaud proposed a unidirectional proxy re-encryption scheme with temporary delegation (IEEE Trans. Inf. Theory, vol. 57, no. 3, pp. 1786–1802, Mar. 2011). They claimed that the scheme is chosen ciphertext secure in the chosen key model. However, their proof has a minor error in the simulation of the re-encryption oracle. The adversary is able to distinguish between the simulated environment and the real attack environment by using responses from the re-encryption oracle. Fortunately, we can amend the proof without any modification of the original scheme.

DOI
10.1109/tit.2012.2236606

Related papers

Improved unidirectional chosen-ciphertext secure proxy re-encryption

Zhao Guo-an, Fang Liming, Wang Jiandong +2 more

At PKC'08, Libert and Vergnaud presented the first construction of unidirectional proxy re-encryption scheme with chosen-ciphertext security in the standard model. The limitation of their scheme is using one time signature. In this paper, an improved unidirectional chosen-ciphertext secure proxy re-encryption scheme is proposed. Our construction is more efficient than Libert and Vergnaud's scheme by avoiding one time signature.

Wireless Communications, Networking and Information Security•Jun 1, 2010•3 citations

CCA-secure unidirectional proxy re-encryption in the adaptive corruption model without random oracles

Chen Min

Up to now, it is still an open question of how to construct a chosen-ciphertext secure unidirectional proxy re-encryption scheme in the adaptive corruption model. To address this problem, we propose a new unidirectional proxy re-encryption scheme, and prove its chosen-ciphertext security in the adaptive corruption model without random oracles. Compared with the best known unidirectional proxy re-encryption scheme proposed by Libert and Vergnaud in PKC’08, our scheme enjoys the advantages of both higher efficiency and stronger security.

Science China Information Sciences•Jan 1, 2010•0 citations

Unidirectional Chosen-Ciphertext Secure Proxy Re-Encryption

Benoît Libert, Damien Vergnaud

In 1998, Blaze, Bleumer and Strauss introduced a cryptographic primitive called proxy re-encryption in which a proxy can transform-without seeing the plaintext-a ciphertext encrypted under one key into an encryption of the same plaintext under another key. The concept has recently drawn renewed interest. Notably, Canetti and Hohenberger showed how to properly define (and realize) chosen-ciphertext security for the primitive. Their system is bidirectional as the translation key allows converting ciphertexts in both directions. This paper presents the first unidirectional proxy re-encryption schemes with chosen-ciphertext security in the standard model (i.e., without the random oracle idealization). The first system provably fits a unidirectional extension of the Canetti-Hohenberger security model. As a second contribution, the paper considers a more realistic adversarial model where attackers may choose dishonest users' keys on their own. It is shown how to modify the first scheme to achieve security in the latter scenario. At a moderate expense, the resulting system provides additional useful properties such as non-interactive temporary delegations. Both constructions are efficient and rely on mild complexity assumptions in bilinear groups. Like the Canetti-Hohenberger scheme, they meet a relaxed flavor of chosen-ciphertext security introduced by Canetti, Krawczyk and Nielsen.

IEEE Transactions on Information Theory•Feb 18, 2011•142 citations

New CCA-Secure Proxy Re-encryption Scheme without Random Oracles

Xu An Wang, Ping Wei, Minqing Zhang

Proxy re-encryption (PRE) allows a ciphertext computed under Alice's public key to be transformed to those which can be decrypted by Bob. In PKC'08, Libert and Vergnaud proposed the first unidirectional RCCA-secure PRE scheme in the standard model. They left the open problem of constructing unidirectional CCA-secure PRE scheme in the standard model open. Until recently, this open problem was solved by Weng et al. and Shao et al. independently. In this paper, based on Shao et al.'s proposal, we give a new efficient CCA-secure PRE scheme without random oracles and prove its security.

International Conference on Computational Intelligence and Security (CIS)•Dec 1, 2010•2 citations

Improving the Security of an Efficient Unidirectional Proxy Re-Encryption Scheme

Sébastien Canard, Julien Devigne, Fabien Laguillaumie

A proxy re-encryption (PRE) scheme allows a designated proxy, that has beforehand received aso-called re-encryption key, to translate a ciphertext intended to one user to a ciphertext intendedto another one. Traditionally, the re-encryption key is generated at the initiative of the initialreceiver and ideally, no secret keys should be known to the proxy. Such scheme is said unidirectionalif the transformation from one user to another does not necessarily imply the possibility tomake the inverse transformation. Regarding the literature on unidirectional proxy re-encryption, itseems hard to prove the strongest security level (namely indistinguishability under chosen ciphertextattacks - IND-CCA) of such schemes. Most of the time, PRE either reaches a chosen-plaintextsecurity or a replayable CCA security. At Africacrypt 2010, Chow, Weng, Yang and Deng proposeda scheme that satisfies CCA security in the random oracle model. However, their modelcan actually be strengthen. Indeed, we show in this paper how to modify this scheme so that itsimproved security achieves a full CCA security. In particular, we now allow the adversary of theCCA security for re-encryption to corrupt the user i′ who is the initial receiver of the challengedciphertext and at the same time to obtain the re-encryption key from i′ to the targeted users. Theresulting scheme is therefore a fully secure PRE which does not rely on pairings, and secure in therandom oracle model. It can be implemented efficiently with any traditional modular arithmetic.

•Jan 1, 2011•21 citations

Collusion-Resistant Identity-Based Proxy Re-Encryption Without Random Oracles

JunJie Qiu, Jungbok Jo, Hoon Jae Lee

In an identity-based proxy re-encryption scheme, a semi-trusted proxy can convert a ciphertext under Alice's public identity into a ciphertext for Bob.The proxy does not know the secret key of Alice or Bob, and also does not know the plaintext during the conversion.In identity-based proxy re-encryption, the collusion of the proxy and a delegatee may result in the decryption of ciphertext for delegator.In this paper, we present a new scheme which can avoid the collusion of proxy and delegatee.Our scheme improves the scheme of Chu and Tzeng while inheriting all useful properties such as unidirectionality and non-interactivity.In our scheme, we get the security by using added secret parameter and change the secret key and re-encryption key.Our sheme is secure against Chosen-Ciphertext Attack (CCA) and collusion attack in the standard model.

International Journal of Security and Its Applications•Sep 30, 2015•5 citations
Libert and Vergnaud proposed a unidirectional proxy re-encryption scheme with temporary delegation (IEEE Trans. Inf. Theory, vol. 57, no. 3, pp. 1786–1802, Mar. 2011). They claimed that the scheme is chosen ciphertext secure in the chosen key model. However, their proof has a minor error in the simulation of the re-encryption oracle. The adversary is able to distinguish between the simulated environment and the real attack environment by using responses from the re-encryption oracle. Fortunately, we can amend the proof without any modification of the original scheme.
Up to now, it is still an open question of how to construct a chosen-ciphertext secure unidirectional proxy re-encryption scheme in the adaptive corruption model. To address this problem, we propose a new unidirectional proxy re-encryption scheme, and prove its chosen-ciphertext security in the adaptive corruption model without random oracles. Compared with the best known unidirectional proxy re-encryption scheme proposed by Libert and Vergnaud in PKC’08, our scheme enjoys the advantages of both higher efficiency and stronger security.
In 1998, Blaze, Bleumer and Strauss introduced a cryptographic primitive called proxy re-encryption in which a proxy can transform-without seeing the plaintext-a ciphertext encrypted under one key into an encryption of the same plaintext under another key. The concept has recently drawn renewed interest. Notably, Canetti and Hohenberger showed how to properly define (and realize) chosen-ciphertext security for the primitive. Their system is bidirectional as the translation key allows converting ciphertexts in both directions. This paper presents the first unidirectional proxy re-encryption schemes with chosen-ciphertext security in the standard model (i.e., without the random oracle idealization). The first system provably fits a unidirectional extension of the Canetti-Hohenberger security model. As a second contribution, the paper considers a more realistic adversarial model where attackers may choose dishonest users' keys on their own. It is shown how to modify the first scheme to achieve security in the latter scenario. At a moderate expense, the resulting system provides additional useful properties such as non-interactive temporary delegations. Both constructions are efficient and rely on mild complexity assumptions in bilinear groups. Like the Canetti-Hohenberger scheme, they meet a relaxed flavor of chosen-ciphertext security introduced by Canetti, Krawczyk and Nielsen.
Proxy re-encryption (PRE) allows a ciphertext computed under Alice's public key to be transformed to those which can be decrypted by Bob. In PKC'08, Libert and Vergnaud proposed the first unidirectional RCCA-secure PRE scheme in the standard model. They left the open problem of constructing unidirectional CCA-secure PRE scheme in the standard model open. Until recently, this open problem was solved by Weng et al. and Shao et al. independently. In this paper, based on Shao et al.'s proposal, we give a new efficient CCA-secure PRE scheme without random oracles and prove its security.
A proxy re-encryption (PRE) scheme allows a designated proxy, that has beforehand received aso-called re-encryption key, to translate a ciphertext intended to one user to a ciphertext intendedto another one. Traditionally, the re-encryption key is generated at the initiative of the initialreceiver and ideally, no secret keys should be known to the proxy. Such scheme is said unidirectionalif the transformation from one user to another does not necessarily imply the possibility tomake the inverse transformation. Regarding the literature on unidirectional proxy re-encryption, itseems hard to prove the strongest security level (namely indistinguishability under chosen ciphertextattacks - IND-CCA) of such schemes. Most of the time, PRE either reaches a chosen-plaintextsecurity or a replayable CCA security. At Africacrypt 2010, Chow, Weng, Yang and Deng proposeda scheme that satisfies CCA security in the random oracle model. However, their modelcan actually be strengthen. Indeed, we show in this paper how to modify this scheme so that itsimproved security achieves a full CCA security. In particular, we now allow the adversary of theCCA security for re-encryption to corrupt the user i′ who is the initial receiver of the challengedciphertext and at the same time to obtain the re-encryption key from i′ to the targeted users. Theresulting scheme is therefore a fully secure PRE which does not rely on pairings, and secure in therandom oracle model. It can be implemented efficiently with any traditional modular arithmetic.
In an identity-based proxy re-encryption scheme, a semi-trusted proxy can convert a ciphertext under Alice's public identity into a ciphertext for Bob.The proxy does not know the secret key of Alice or Bob, and also does not know the plaintext during the conversion.In identity-based proxy re-encryption, the collusion of the proxy and a delegatee may result in the decryption of ciphertext for delegator.In this paper, we present a new scheme which can avoid the collusion of proxy and delegatee.Our scheme improves the scheme of Chu and Tzeng while inheriting all useful properties such as unidirectionality and non-interactivity.In our scheme, we get the security by using added secret parameter and change the secret key and re-encryption key.Our sheme is secure against Chosen-Ciphertext Attack (CCA) and collusion attack in the standard model.