Survey of security services on group communications
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paper_title: Secure group communications using key graphs

paper_content:

Many emerging applications (e.g., teleconference, real-time information services, pay per view, distributed interactive simulation, and collaborative work) are based upon a group communications model, i.e., they require packet delivery from one or more authorized senders to a very large number of authorized receivers. As a result, securing group communications (i.e., providing confidentiality, integrity, and authenticity of messages delivered between group members) will become a critical networking issue.In this paper, we present a novel solution to the scalability problem of group/multicast key management. We formalize the notion of a secure group as a triple (U,K,R) where U denotes a set of users, K a set of keys held by the users, and R a user-key relation. We then introduce key graphs to specify secure groups. For a special class of key graphs, we present three strategies for securely distributing rekey messages after a join/leave, and specify protocols for joining and leaving a secure group. The rekeying strategies and join/leave protocols are implemented in a prototype group key server we have built. We present measurement results from experiments and discuss performance comparisons. We show that our group key management service, using any of the three rekeying strategies, is scalable to large groups with frequent joins and leaves. In particular, the average measured processing time per join/leave increases linearly with the logarithm of group size.
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paper_title: Scalable Secure Group Communication over IP Multicast

paper_content:

We introduce and analyze a scalable rekeying scheme for implementing secure group communications Internet protocol multicast. We show that our scheme incurs constant processing, message, and storage overhead for a rekey operation when a single member joins or leaves the group, and logarithmic overhead for bulk simultaneous changes to the group membership. These bounds hold even when group dynamics are not known a priori. Our rekeying algorithm requires a particular clustering of the members of the secure multicast group. We describe a protocol to achieve such clustering and show that it is feasible to efficiently cluster members over realistic Internet-like topologies. We evaluate the overhead of our own rekeying scheme and also of previously published schemes via simulation over an Internet topology map containing over 280 000 routers. Through analysis and detailed simulations, we show that this rekeying scheme performs better than previous schemes for a single change to group membership. Further, for bulk group changes, our algorithm outperforms all previously known schemes by several orders of magnitude in terms of actual bandwidth usage, processing costs, and storage requirements.
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paper_title: Secure group communication using robust contributory key agreement

paper_content:

Contributory group key agreement protocols generate group keys based on contributions of all group members. Particularly appropriate for relatively small collaborative peer groups, these protocols are resilient to many types of attacks. Unlike most group key distribution protocols, contributory group key agreement protocols offer strong security properties such as key independence and perfect forward secrecy. We present the first robust contributory key agreement protocol resilient to any sequence of group changes. The protocol, based on the Group Diffie-Hellman contributory key agreement, uses the services of a group communication system supporting virtual synchrony semantics. We prove that it provides both virtual synchrony and the security properties of Group Diffie-Hellman, in the presence of any sequence of (potentially cascading) node failures, recoveries, network partitions, and heals. We implemented a secure group communication service, Secure Spread, based on our robust key agreement protocol and Spread group communication system. To illustrate its practicality, we compare the costs of establishing a secure group with the proposed protocol and a protocol based on centralized group key management, adapted to offer equivalent security properties.
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paper_title: Hierarchical group access control for secure multicast communications

paper_content:

Many group communications require a security infrastructure that ensures multiple levels of access control for group members. While most existing group key management schemes are designed for single level access control, we present a multi-group key management scheme that achieves hierarchical group access control. Particularly, we design an integrated key graph that maintains keying material for all members with different access privileges. It also incorporates new functionalities that are not present in conventional multicast key management, such as user relocation on the key graph. Analysis is performed to evaluate the storage and communication overhead associated key management. Comprehensive simulations are performed for various application scenarios where users statistical behavior is modelled using a discrete Markov chain. Compared with applying existing key management schemes directly to the hierarchical access control problem, the proposed scheme significantly reduces the overhead associated with key management and achieves better scalability.
---
paper_title: A centralized key management scheme for hierarchical access control

paper_content:

Key management schemes are used to provide access control to data streams for legitimate users. The users often have certain partially ordered relations, while data streams also form some partially ordered relations. Previous key management schemes have failed to take into consideration either the user relations or data stream relations. We propose a centralized key management scheme for hierarchical access control that considers both partially ordered users and partially ordered data streams. Our scheme improves the efficiency of key management by encrypting multiple equivalent data streams with a single data encryption key, instead of encrypting each data stream with a unique data encryption key in the multi-group key management scheme (Sun, Y. and Ray Liu, K.J., IEEE INFOCOM, 2004). We develop a simulation model to evaluate the performance of our proposed scheme. Simulation results show that our scheme reduces at least 20% of storage overhead at every user and rekey overhead compared to the multi-group key management scheme.
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paper_title: A Practical and Provably Secure Coalition-Resistant Group Signature Scheme

paper_content:

A group signature scheme allows a group member to sign messages anonymously on behalf of the group. However, in the case of a dispute, the identity of a signature's originator can be revealed (only) by a designated entity. The interactive counterparts of group signatures are identity escrow schemes or group identification scheme with revocable anonymity. This work introduces a new provably secure group signature and a companion identity escrow scheme that are significantly more efficient than the state of the art. In its interactive, identity escrow form, our scheme is proven secure and coalition-resistant under the strong RSA and the decisional Diffie-Hellman assumptions. The security of the non-interactive variant, i.e., the group signature scheme, relies additionally on the Fiat-Shamir heuristic (also known as the random oracle model).
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paper_title: Threshold signature scheme with multiple signing policies

paper_content:

Based on one cryptographic assumption, a basic threshold scheme is derived which allows a group of users to share multiple secrets. The major advantage of the threshold scheme is that only one secret shadow needs to be kept by each user. The basic threshold scheme is applied to design an efficient threshold signature scheme with multiple signing policies. The threshold signature scheme with multiple signing policies allows multiple secret keys to be shared among a group of users, and each secret key has its specific threshold value. Different secret keys can be used to sign documents depending on the significance of the documents. Once the number of cooperated users is greater than or equal to the threshold value of the group secret key, then they can co-operate to create group signatures. Similarly, each user keeps only one secret shadow.
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paper_title: Provably secure and ID-based group signature scheme

paper_content:

There are two important directions in group signature scheme: ID-based group signature scheme and provably secure group signature scheme. We first analyze the advantages and flaws of these two directions, and propose a provably secure ID-based group signature scheme basing on the ACJT group signature scheme. Compared with prior ID-Based group signature scheme, our scheme is provably secure in random oracle model. Compared with the ACJT scheme, our scheme is ID-Based and strong nonrepudiation.
---
paper_title: A Practical and Provably Secure Coalition-Resistant Group Signature Scheme

paper_content:

A group signature scheme allows a group member to sign messages anonymously on behalf of the group. However, in the case of a dispute, the identity of a signature's originator can be revealed (only) by a designated entity. The interactive counterparts of group signatures are identity escrow schemes or group identification scheme with revocable anonymity. This work introduces a new provably secure group signature and a companion identity escrow scheme that are significantly more efficient than the state of the art. In its interactive, identity escrow form, our scheme is proven secure and coalition-resistant under the strong RSA and the decisional Diffie-Hellman assumptions. The security of the non-interactive variant, i.e., the group signature scheme, relies additionally on the Fiat-Shamir heuristic (also known as the random oracle model).
---
paper_title: Framework for anonymity in IP-multicast environments

paper_content:

The importance of the global Internet for conferencing and entertainment increases with the expanding availability of multicast capable networks. As with other applications and services, security concerns in multicast environments become a major topic for the research community. While there are a lot of publications available analysing the problems of group authentication and privacy, the aspect of anonymity in multicast environments has seldom been considered yet. This paper focuses on a fundamental overview of this topic, introduces a concept for providing anonymity for both senders and receivers in a multicast scenario and presents a optimisation concept for the system.
---
paper_title: Threshold signature scheme with multiple signing policies

paper_content:

Based on one cryptographic assumption, a basic threshold scheme is derived which allows a group of users to share multiple secrets. The major advantage of the threshold scheme is that only one secret shadow needs to be kept by each user. The basic threshold scheme is applied to design an efficient threshold signature scheme with multiple signing policies. The threshold signature scheme with multiple signing policies allows multiple secret keys to be shared among a group of users, and each secret key has its specific threshold value. Different secret keys can be used to sign documents depending on the significance of the documents. Once the number of cooperated users is greater than or equal to the threshold value of the group secret key, then they can co-operate to create group signatures. Similarly, each user keeps only one secret shadow.
---
paper_title: Hierarchical group access control for secure multicast communications

paper_content:

Many group communications require a security infrastructure that ensures multiple levels of access control for group members. While most existing group key management schemes are designed for single level access control, we present a multi-group key management scheme that achieves hierarchical group access control. Particularly, we design an integrated key graph that maintains keying material for all members with different access privileges. It also incorporates new functionalities that are not present in conventional multicast key management, such as user relocation on the key graph. Analysis is performed to evaluate the storage and communication overhead associated key management. Comprehensive simulations are performed for various application scenarios where users statistical behavior is modelled using a discrete Markov chain. Compared with applying existing key management schemes directly to the hierarchical access control problem, the proposed scheme significantly reduces the overhead associated with key management and achieves better scalability.
---
paper_title: Secure group communications using key graphs

paper_content:

Many emerging applications (e.g., teleconference, real-time information services, pay per view, distributed interactive simulation, and collaborative work) are based upon a group communications model, i.e., they require packet delivery from one or more authorized senders to a very large number of authorized receivers. As a result, securing group communications (i.e., providing confidentiality, integrity, and authenticity of messages delivered between group members) will become a critical networking issue.In this paper, we present a novel solution to the scalability problem of group/multicast key management. We formalize the notion of a secure group as a triple (U,K,R) where U denotes a set of users, K a set of keys held by the users, and R a user-key relation. We then introduce key graphs to specify secure groups. For a special class of key graphs, we present three strategies for securely distributing rekey messages after a join/leave, and specify protocols for joining and leaving a secure group. The rekeying strategies and join/leave protocols are implemented in a prototype group key server we have built. We present measurement results from experiments and discuss performance comparisons. We show that our group key management service, using any of the three rekeying strategies, is scalable to large groups with frequent joins and leaves. In particular, the average measured processing time per join/leave increases linearly with the logarithm of group size.
---
paper_title: A centralized key management scheme for hierarchical access control

paper_content:

Key management schemes are used to provide access control to data streams for legitimate users. The users often have certain partially ordered relations, while data streams also form some partially ordered relations. Previous key management schemes have failed to take into consideration either the user relations or data stream relations. We propose a centralized key management scheme for hierarchical access control that considers both partially ordered users and partially ordered data streams. Our scheme improves the efficiency of key management by encrypting multiple equivalent data streams with a single data encryption key, instead of encrypting each data stream with a unique data encryption key in the multi-group key management scheme (Sun, Y. and Ray Liu, K.J., IEEE INFOCOM, 2004). We develop a simulation model to evaluate the performance of our proposed scheme. Simulation results show that our scheme reduces at least 20% of storage overhead at every user and rekey overhead compared to the multi-group key management scheme.
---
paper_title: Secure group communication using robust contributory key agreement

paper_content:

Contributory group key agreement protocols generate group keys based on contributions of all group members. Particularly appropriate for relatively small collaborative peer groups, these protocols are resilient to many types of attacks. Unlike most group key distribution protocols, contributory group key agreement protocols offer strong security properties such as key independence and perfect forward secrecy. We present the first robust contributory key agreement protocol resilient to any sequence of group changes. The protocol, based on the Group Diffie-Hellman contributory key agreement, uses the services of a group communication system supporting virtual synchrony semantics. We prove that it provides both virtual synchrony and the security properties of Group Diffie-Hellman, in the presence of any sequence of (potentially cascading) node failures, recoveries, network partitions, and heals. We implemented a secure group communication service, Secure Spread, based on our robust key agreement protocol and Spread group communication system. To illustrate its practicality, we compare the costs of establishing a secure group with the proposed protocol and a protocol based on centralized group key management, adapted to offer equivalent security properties.
---
paper_title: Xor-trees for efficient anonymous multicast and reception

paper_content:

We examine the problem of efficient anonymous multicast and reception in general communication networks. We present algorithms that achieve anonymous communication, are protected against traffic analysis, and require O (1) amortized communication complexity on each link and low computational comlexity. The algorithms support sender anonymity, receiver(s) anonymity, or sender-receiver anonymity.
---
paper_title: Provably secure and ID-based group signature scheme

paper_content:

There are two important directions in group signature scheme: ID-based group signature scheme and provably secure group signature scheme. We first analyze the advantages and flaws of these two directions, and propose a provably secure ID-based group signature scheme basing on the ACJT group signature scheme. Compared with prior ID-Based group signature scheme, our scheme is provably secure in random oracle model. Compared with the ACJT scheme, our scheme is ID-Based and strong nonrepudiation.
---
paper_title: Framework for anonymity in IP-multicast environments

paper_content:

The importance of the global Internet for conferencing and entertainment increases with the expanding availability of multicast capable networks. As with other applications and services, security concerns in multicast environments become a major topic for the research community. While there are a lot of publications available analysing the problems of group authentication and privacy, the aspect of anonymity in multicast environments has seldom been considered yet. This paper focuses on a fundamental overview of this topic, introduces a concept for providing anonymity for both senders and receivers in a multicast scenario and presents a optimisation concept for the system.
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paper_title: KHIP—a scalable protocol for secure multicast routing

paper_content:

We present Keyed HIP (KHIP), a secure, hierarchical multicast routing protocol. We show that other shared-tree multicast routing protocols are subject to attacks against the multicast routing infrastructure that can isolate receivers or domains or introduce loops into the structure of the multicast routing tree. KHIP changes the multicast routing model so that only trusted members are able to join the multicast tree. This protects the multicast routing against attacks that could form branches to unauthorized receivers, prevents replay attacks and limits the effects of flooding attacks. Untrusted routers that are present on the path between trusted routers cannot change the routing and can mount no denial-of-service attack stronger than simply dropping control messages. KHIP also provides a simple mechanism for distributing data encryption keys while adding little overhead to the protocol.
---
paper_title: Xor-trees for efficient anonymous multicast and reception

paper_content:

We examine the problem of efficient anonymous multicast and reception in general communication networks. We present algorithms that achieve anonymous communication, are protected against traffic analysis, and require O (1) amortized communication complexity on each link and low computational comlexity. The algorithms support sender anonymity, receiver(s) anonymity, or sender-receiver anonymity.
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paper_title: A secure group solution for multi-agent ec system

paper_content:

Mobile agent technology applied into EC is facing many problems. Security should be the first concern. But in large scale multi-agent systems, the most challenging problems encountered are locating and communicating of these autoprocessing agents. Some approaches have used several different methods to solve these problems. But unfortunately, they were not satisfied either for their complexity, poor performance or their lack of applicability. In our approach, we propose a secure group communication solution toward the security, locating and communication problems. We differentiated the ”Agent-Based” Multicast concept from the traditional ”Host-Based” Multicast. We then described the requirements for providing secure group services and introduce the key distribution method. A cryptographic method is complemented for further protect the agents. Finally, we analyzed the security and performance issues and conclude our solution.
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paper_title: A Secure Group Communication Framework in Private Personal Area Networks (P-PANs)

paper_content:

One of the next promising generation networks is personal networks where a user can make ad-hoc networks with his/her personal devices. However, the present security mechanism does not consider at all what happens whenever a mobile node (device) is compromised, lost or stolen. Since a user may hold many different types of devices, the leakage of stored secrets sometimes results in the complete breakdown of the intended security level. For that, we propose two Leakage-Resilient and Forward-Secure Authenticated Key Exchange (LRFS-AKE1 and LRFS-AKE2) protocols where the former is used to authenticate a device when its owner is present whereas the latter is used in the other case. These protocols guarantee not only forward secrecy of the shared key between device and its server but also a new additional layer of security against leakage of stored secrets. Furthermore, we give a secure group communication framework, based on the LRFS-AKE1 and LRFS-AKE2 protocols, in Private Personal Area Networks (P-PANs) which provides a group key privacy against the involved server who does not deviate the protocol.
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paper_title: Efficient secure group management for SSM

paper_content:

We propose an approach to channel key management in the architecture S-SSM, we designed to secure SSM communication. S-SSM defines two mechanisms for access control and content protection. The first one is carried out through subscriber authentication and access permission. The second is realized through the management of a unique key, called the channel key, k/sub ch/, shared among the sender and subscribers. The management of k/sub ch/ is based on a novel distributed encryption scheme that enables an entity to efficiently add and remove a subscriber without affecting other subscribers.
---
paper_title: A Secure Group Communication Framework in Private Personal Area Networks (P-PANs)

paper_content:

One of the next promising generation networks is personal networks where a user can make ad-hoc networks with his/her personal devices. However, the present security mechanism does not consider at all what happens whenever a mobile node (device) is compromised, lost or stolen. Since a user may hold many different types of devices, the leakage of stored secrets sometimes results in the complete breakdown of the intended security level. For that, we propose two Leakage-Resilient and Forward-Secure Authenticated Key Exchange (LRFS-AKE1 and LRFS-AKE2) protocols where the former is used to authenticate a device when its owner is present whereas the latter is used in the other case. These protocols guarantee not only forward secrecy of the shared key between device and its server but also a new additional layer of security against leakage of stored secrets. Furthermore, we give a secure group communication framework, based on the LRFS-AKE1 and LRFS-AKE2 protocols, in Private Personal Area Networks (P-PANs) which provides a group key privacy against the involved server who does not deviate the protocol.
---
paper_title: Efficient secure group management for SSM

paper_content:

We propose an approach to channel key management in the architecture S-SSM, we designed to secure SSM communication. S-SSM defines two mechanisms for access control and content protection. The first one is carried out through subscriber authentication and access permission. The second is realized through the management of a unique key, called the channel key, k/sub ch/, shared among the sender and subscribers. The management of k/sub ch/ is based on a novel distributed encryption scheme that enables an entity to efficiently add and remove a subscriber without affecting other subscribers.
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Title: Survey of Security Services on Group Communications

Section 1: Introduction
Description 1: Provide an overview of group communication systems, the need for security services, and the role of cryptographic materials.

Section 2: Security requirements and services in group communications
Description 2: Discuss the six security requirements in group communications and the five security services required to meet these needs.

Section 3: Performance attributes for evaluating secure GCSs
Description 3: Explain the fundamental and service-specific attributes used to evaluate and compare different secure group communication systems (SGCs).

Section 4: Security services for group communications
Description 4: Detail the essential security services that meet the security requirements discussed earlier, including group key management and group access control.

Section 5: Group communication-oriented networks
Description 5: Review some SGC frameworks implemented on existing networks, such as multi-agent systems, personal area networks, and IP multicast networks.

Section 6: Challenging factors in designing secure GCSs
Description 6: Summarize various attributes and considerations in designing secure and high-performance group communication systems.

Section 7: Conclusions
Description 7: Provide a summary and better understanding of security requirements and services in GCSs. Mention the evaluation attributes used and the comparisons made in the study.