Internet DRAFT - draft-park-mls-multiple-groups-requirement
draft-park-mls-multiple-groups-requirement
Network Working Group M. Park
Internet-Draft Soongsil University
Intended status: Informational November 20, 2018
Expires: May 24, 2019
Multiple group membership
draft-park-mls-multiple-groups-requirement-00
Abstract
This document proposes a functional requirement of Message Level
Security (MLS) which provide an efficient management for multiple
groups. Although MLS defines an architecture and an abstract
protocol for a secure group communication, it overlooks the need of
multiple groups. This document describes a usecase of the multiple
groups, and the need for an efficient multiple group membership
management.
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This Internet-Draft will expire on May 24, 2019.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Re-keying for membership change . . . . . . . . . . . . . . . 2
4. Multiple groups scenario . . . . . . . . . . . . . . . . . . 3
5. Multiple group membership . . . . . . . . . . . . . . . . . . 4
6. Informative References . . . . . . . . . . . . . . . . . . . 4
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
With the emergence of diverse group-based applications, e.g. a
channel-based charged TV or telematics services, multiple group
applications are likely to coexist, and users may have multiple
memberships. Of course, although the functional requirements defined
in the mls architecture draft can satisfy the multiple membership
management, we need to consider the efficient management of multiple
membership. This document mentions the inefficiency which may occur
in the multiple membership management and the motivation of the
functional requirement, multiple group membership.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
3. Re-keying for membership change
Let us consider a situation where a member is about to leave a group.
Before this member leaves, all the members have shared a group key to
encrypt/decrypt messages among themselves. After the member leaves,
the old group key must be revoked and updated with a new group key.
This rekeying process may cause a lot of key management overhead.
Since the existing members do not have any shared secret keys except
for the old group key, a new group key should be distributed to these
members in a secure manner. As a result, it is obvious that the more
the number of users in a group service, the larger the rekeying
overhead would be.
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4. Multiple groups scenario
There can be various group messaging services. Generally, the group
messaging services can be considered as the commercial services such
as a charged TV streaming service, a telematics service, and an
information service (Sports or stock). Let us assume these three
services are Delivery Services (DS) as shown in Figure 1. In this
case, there will be at least three groups for the three services,
each of which should be managed according to the membership records
of the DSs. Moreover, if the subscription to a DS is charged for
either each channel (Ch1, Ch2, and Ch3) or content (sports and
stock), the service provider should manage the additional user groups
(e.g., channel-based or content-based groups) for accurate accounting
like Figure 2. As a result, the management overhead stemming from
membership management including rekeying can significantly increase
due to the number of such groups.
---------------- -------------- -----------------
| A Charged TV | | Telematics | | Information |
| | | Service | | Service |
|<Ch1><Ch2><Ch3> | | | | <Sports> <Stock>|
---------------- -------------- -----------------
\ / \________________ / |
\ / _____\_________/ |
\ / / \ |
------- ------ ------- -------
| User0 | | User1 | | User2 | | User3 |
------- ------ ------- -------
Figure 1: Multiple groups scenario
Ch1 group Ch2 group Ch3 group
**************** **************** ****************
* ------- * * ------- * * ------- *
*| User0 | ...* *| User1 | ... * *| User2 | ... *
* ------- * * ------- * * ------- *
**************** **************** ****************
Telematics group Sports group Stock group
**************** **************** ****************
* ------- * * ------- * * ------- *
*| User2 | ...* *| User1 | ... * *| User3 | ... *
* ------- * * ------- * * ------- *
**************** **************** ****************
Figure 2: Six delivery service groups
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5. Multiple group membership
The multiple group scenario in the previous section can be
implemented with multiple independent groups, where each service
group has an independent AS. However, a single service provider may
manage multiple groups, e.g., multiple channel groups in a channel-
based charged service. In this case, the service provider should
have multiple independent groups corresponding to each channel, which
may increase the management cost such as many Ass as the number of
groups and re-keying. Therefore, the protocol should be able to
allow a single Authentication Service to manage multiple group
memberships in order to support more than two Delivery Services as
shown in Figure 3.
---------------- -------------- --------------
| Authentication | | Delivery | | Delivery |
| Service (AS) | | Service(DS1) | | Service(DS2) |
---------------- -------------- --------------
Multiple memberships / \ / |
*********************************************************
* / ________\___/ | *
* / / \ | *
* ---------- ---------- ---------- *
* | Client 0 | | Client 1 | | Client N | *
* ---------- ---------- ---------- *
* ............................ ........... *
* Member 0 Member 1 *
* *
*********************************************************
Figure 3: Multiple membership
6. Informative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
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Appendix A. Acknowledgements
This work was supported by Institute for Information & communications
Technology Promotion(IITP) grant funded by the Korea government(MSIT)
(No.2018-0-00254, SDN security technology development).
Author's Address
Minho Park
School of Electronic Engineering
Soongsil University
369, Sangdo-ro, Dongjak-gu
Seoul, Seoul 06978
Republic of Korea
Phone: +82 2 828 7176
EMail: mhp@ssu.ac.kr
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