Dual encryption protocol for scalable secure group communication

Abstract

A logical tree structure and method for managing membership in a multicast group provides scalability and security from internal attacks. The structure defines key groups and subgroups, with each subgroup having a subgroup manager. Dual encryption allows the sender of the multicast data to manage distribution of a first set of encryption keys whereas the individual subgroup managers manage the distribution of a second set of encryption keys. The two key sets allow the sender to delegate much of the group management responsibilities without compromising security because a key from each set is required to access the multicast data. Security is further maintained via a method in which subgroup managers can be either member subgroup managers or participant subgroup managers. Access to both keys is provided to member subgroup managers whereas access to only one key is provided to participant subgroup managers. Nodes can be added without the need to generate a new encryption key at the top level which provides improved scalability.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001]This application claims the benefit of U.S. Provisional Application No. 60 / 142,495, filed on Jul. 6, 1999. The disclosure of the above application is incorporated herein by reference.<?insert-end id="INS-S-00001" ?>BACKGROUND AND SUMMARY OF THE INVENTION[0002]The present invention relates generally to multicasting. More particularly, the invention relates to a dual encryption protocol for scalable secure group communication.[0003]With the widespread use of the Internet, securing data transmissions is an important requirement for many applications. Several protocols exist to address security in data networks with respect to unicasting. Unfortunately, these protocols cannot be easily extended to protect multicast data.[0004]Multicasting poses several problems that do not come up in securing unicast data transfers. First, multicast addresses are not private, which enables any interested host to join the multicast session without any h...

AI Technical Summary

Benefits of technology

[0009]Hierarchical schemes distribute encryption keys via a distribution tree. Two classes of hierarchical protocols have been proposed. The first class uses a hierarchy of keys while the second group uses a hierarchy of nodes to achieve scalability.

Problems solved by technology

Unfortunately, these protocols cannot be easily extended to protect multicast data.

Multicasting poses several problems that do not come up in securing unicast data transfers.

Next, multicast data is transmitted over many channels of the network, which presents multiple opportunities for attacks such as eavesdropping.

Furthermore, any host in the Internet can send irrelevant data to the multicast group, which may cause congestion.

Finally, adversaries can possibly disrupt the multicast protocol itself by posing as legitimate members of the group.

In other words, members of a multicast session must not be able to access the multicast data transmitted before their membership has begun or after their membership has expired.

Thus these schemes suffer from the 1 affects n scalability problem.

Trusting all the members makes this protocol vulnerable to security attacks from inside the group.

Hierarchical key based schemes suffer from the 1 affects n scalability problem.

But they offer no mechanism to hide secure multicast data from the internal nodes.

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