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Improving Choi et al.'s ID-based Authenticated Group Key Agreement Scheme at PKC2004

Hyewon Park, Kyusuk Han, Chan Yeob Yeun, Kwangjo Kim

Published Jan 1, 2008• 3 citations
OpenAlex

Abstract

In modern network computing, authenticated group key agreement (AGKA) is important for conferencing. After Shamir [2] proposed the ID-based cryptosystem in 1984, the various applications on the ID-based cryptosystem have been actively studied, due to the simple key management complexity. For the AGKA, Choi et al. [16] proposed an ID-based authenticated group key agreement with bilinear maps, which was extended from Burmester and Desmedt conference key agreement protocol [5]. After that, Zhang and Chen [15] showed that the impersonation attack on Choi et al. protocol is feasible when two malicious users have the previous authentication transcripts of the entity. Shim [19] showed that the insider colluding attacks can be done without the previous transcripts. In this paper, we propose an improved ID-based AGKA. In our scheme, Key Generation Center (KGC) keeps the list of randomized user index instead of only generating private key. The random user indexing means KGC shuffles the order of users’ indices by randomizing to hide it so that the malicious users cannot know the order. KGC also verify all users than only verifies 3 users in Choi et al.’s protocol. Our protocol can prevent replay attack of Zhang and Chen and insider colluding attack of Shim.

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Identity-based group key exchange protocols resistant to colluding attacks

Yunjie Jiang

An ID-based authenticated group key agreement (AGKA) protocol allows a group of members to share a key and provide an assurance of key sharing with an intended group with the user's identity, which is used for conferencing environments. In 2004, Choi et al proposed an ID-based authenticated group key agreement with bilinear maps (also called CHL protocols), which was extended from Burmester and Desmedt conference key agreement protocols. Unfortunately, their protocols were found to be vulnerable to the insider attacks in which cases that the two malicious users have the previous authentication transcripts of the party by Zhang, Chen and Shim. In this paper, we proposed an improved ID-based AGKA. In our scheme, each session has a unique session identity which is published by Key Generation Center. With such unique session identity binding to each session, our protocols can prevent the insider attack. Especially, our protocols can not enhance the computationally cost and it is still efficient.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jan 11, 2012•0 citations

Improved ID-based Authenticated Group Key Agreement Secure Against Impersonation Attack by Insider

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Many conference systems over the Internet require authenticated group key agreement (AGKA) for secure and reliable communication. After Shamir [1] proposed the ID-based cryptosystem in 1984, ID-based AGKA protocols have been actively studied because of the simple public key management. In 2006, Zhou et al. [12] proposed two-round ID-based AGKA protocol which is very efficient in communication and computation complexity. However, their protocol does not provide user identification and suffers from the impersonation attack by malicious participants. In this paper, we propose improved ID-based AGKA protocol to prevent impersonation attack from Zhou et al.'s protocol. In our protocol, the malicious insider cannot impersonate another participants even if he knows the ephemeral group secret value. Moreover, our protocol reduces the computation cost from Zhou et al.'s protocol.

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Comments on an ID-Based Authenticated Group Key Agreement Protocol with Withstanding Insider Attacks

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In PKC 2004, Choi et al. proposed an ID-based authenticated group key agreement (AGKA) protocol using bilinear pairings. Unfortunately, their protocol suffered from an impersonation attack and an insider colluding attack. In 2008, Choi et al. presented an improvement to resist insider attacks. In their modified protocol, they used an ID-based signature scheme on transcripts for binding them in a session to prevent replay of transcripts. In particular, they smartly used the batch verification technique to reduce the computational cost. In this paper, we first show that Choi et al.'s modified AGKA protocol still suffers from an insider colluding attack. Then, we prove that the batch verification of the adopted ID-based signature scheme in their modified protocol suffers from a forgery attack.

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In 2004, Choi et al. proposed an ID-based authenticated group key agreement. Unfortunately, their protocol was found to be vulnerable to the insider attacks by Zhang, Chen and Shim. To prevent insider attacks, Shim presented a modification of Choi et al.'s protocol. In this letter, we first show that Shim's modification is still insecure against insider attacks. We then present a modification of Choi et al.'s protocol that resists insider attacks. The counter-measure uses an ID-based signature on transcripts in order to bind them in a session. This prevents any replay of transcripts. Especially, by applying ID-based batch verification, the proposed one still consists of two rounds and is computationally efficient.

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Analysis and Improvement of Group Key Agreement Protocol ID-AGKA

HE Da-ke

A more security analysis on the ID-based Authenticated Group Key Agreement(ID-AGKA) is given and it is found that the ID-based AGKA does not resist outsider attack, that is, an adversary can make a group session key inconsistent, which can not be detected by the users in the group however. An improvement of the AGKA scheme is proposed. Security analysis shows the scheme can resist outside attack.

Jisuanji gongcheng•Jan 1, 2009•1 citation
In modern network computing, authenticated group key agreement (AGKA) is important for conferencing. After Shamir [2] proposed the ID-based cryptosystem in 1984, the various applications on the ID-based cryptosystem have been actively studied, due to the simple key management complexity. For the AGKA, Choi et al. [16] proposed an ID-based authenticated group key agreement with bilinear maps, which was extended from Burmester and Desmedt conference key agreement protocol [5]. After that, Zhang and Chen [15] showed that the impersonation attack on Choi et al. protocol is feasible when two malicious users have the previous authentication transcripts of the entity. Shim [19] showed that the insider colluding attacks can be done without the previous transcripts. In this paper, we propose an improved ID-based AGKA. In our scheme, Key Generation Center (KGC) keeps the list of randomized user index instead of only generating private key. The random user indexing means KGC shuffles the order of users’ indices by randomizing to hide it so that the malicious users cannot know the order. KGC also verify all users than only verifies 3 users in Choi et al.’s protocol. Our protocol can prevent replay attack of Zhang and Chen and insider colluding attack of Shim.
An ID-based authenticated group key agreement (AGKA) protocol allows a group of members to share a key and provide an assurance of key sharing with an intended group with the user's identity, which is used for conferencing environments. In 2004, Choi et al proposed an ID-based authenticated group key agreement with bilinear maps (also called CHL protocols), which was extended from Burmester and Desmedt conference key agreement protocols. Unfortunately, their protocols were found to be vulnerable to the insider attacks in which cases that the two malicious users have the previous authentication transcripts of the party by Zhang, Chen and Shim. In this paper, we proposed an improved ID-based AGKA. In our scheme, each session has a unique session identity which is published by Key Generation Center. With such unique session identity binding to each session, our protocols can prevent the insider attack. Especially, our protocols can not enhance the computationally cost and it is still efficient.
Many conference systems over the Internet require authenticated group key agreement (AGKA) for secure and reliable communication. After Shamir [1] proposed the ID-based cryptosystem in 1984, ID-based AGKA protocols have been actively studied because of the simple public key management. In 2006, Zhou et al. [12] proposed two-round ID-based AGKA protocol which is very efficient in communication and computation complexity. However, their protocol does not provide user identification and suffers from the impersonation attack by malicious participants. In this paper, we propose improved ID-based AGKA protocol to prevent impersonation attack from Zhou et al.'s protocol. In our protocol, the malicious insider cannot impersonate another participants even if he knows the ephemeral group secret value. Moreover, our protocol reduces the computation cost from Zhou et al.'s protocol.
In PKC 2004, Choi et al. proposed an ID-based authenticated group key agreement (AGKA) protocol using bilinear pairings. Unfortunately, their protocol suffered from an impersonation attack and an insider colluding attack. In 2008, Choi et al. presented an improvement to resist insider attacks. In their modified protocol, they used an ID-based signature scheme on transcripts for binding them in a session to prevent replay of transcripts. In particular, they smartly used the batch verification technique to reduce the computational cost. In this paper, we first show that Choi et al.'s modified AGKA protocol still suffers from an insider colluding attack. Then, we prove that the batch verification of the adopted ID-based signature scheme in their modified protocol suffers from a forgery attack.
In 2004, Choi et al. proposed an ID-based authenticated group key agreement. Unfortunately, their protocol was found to be vulnerable to the insider attacks by Zhang, Chen and Shim. To prevent insider attacks, Shim presented a modification of Choi et al.'s protocol. In this letter, we first show that Shim's modification is still insecure against insider attacks. We then present a modification of Choi et al.'s protocol that resists insider attacks. The counter-measure uses an ID-based signature on transcripts in order to bind them in a session. This prevents any replay of transcripts. Especially, by applying ID-based batch verification, the proposed one still consists of two rounds and is computationally efficient.
Recently, Choi et al. proposed an ID-based authenticated group key agreement with bilinear maps. Subsequently, Zhang and Chen showed that the protocol does not provide authenticity as claimed by replaying transcripts of the past session. To prevent those replay attacks, they suggest adding a time parameter to the message being signed. However, despite of such a modification, we show that the protocol is still insecure against insider colluding attacks without replaying transcripts of the past session.