# Presentation: 577808

## Secure and Reliable Group Communication

- Mary R. Thompson - LBNL
- Gene Tsudik - USC/ISI (     UC Irvine)

- DoE NGI PI Meeting, Washington D.C., October 4-5, 1999

## Goals

- investigate group key management protocols and their access control requirements
- investigate authorization policies for dynamic peer groups.
- provide an integrated prototype of a general-purpose secure, reliable group communication system.

- DoE NGI PI Meeting, Washington D.C., October 4-5, 1999

## Technical Challenges and Innovations

- Define dynamic group membership and admission policies.
- Implement authorization policies in tandem with key agreement when group membership changes.
- Integrate secure authorized groups with a reliable group communication protocol.
- Design provably correct, robust multi-party protocols immune to failures, partitions, heals and other membership changes

- DoE NGI PI Meeting, Washington D.C., October 4-5, 1999

## Technologies useful to others

- Security library (and API) bundled with reliable group communication
- To include access control policies for admission and continuing membership in groups
- Suitable for collaborative applications (many-to-many dynamic peer groups, not multicast!)
- GAA-API for groups...

- DoE NGI PI Meeting, Washington D.C., October 4-5, 1999

**Notes:**
1 - group key agreement, encryption

2. Can this be a library - We need to define the API

## Architecture

- Reliable Group Communication
- (TOTEM)

- Secure Group
- Communication

- Access Control

- Key Management

- Encryption

- Network layer
- (UDP)

- Certificate
- Support
- (X.509, LDAP)

- Cryptographic
- Library
- (OpenSSL)

- Group Security
- (CLIQUES)

- Collaborative
- Application

- DoE NGI PI Meeting, Washington D.C., October 4-5, 1999

## Akenti - Current

- Authorization based on policy expressed in (distributed) signed certificates
- Requires some initial static policy about trust relations
- Akenti performance is acceptable for a limited number of policy certificates.
- about 2 seconds per certificate
- more flexible caching may help.

- DoE NGI PI Meeting, Washington D.C., October 4-5, 1999

## Akenti Extensions

- Dynamic groups require a more dynamic policy update mechanism.
- Including removing policy files
- May want to issue short-lived authorization certificates (capabilites) to separate authorization function from group joining operation.

- DoE NGI PI Meeting, Washington D.C., October 4-5, 1999

## CLIQUES- Current

- Group creation - no permanent group controller needed.
- Single member add and remove
- Multiple member add and remove
- Fusion and fission of groups
- Periodic key refresh

- DoE NGI PI Meeting, Washington D.C., October 4-5, 1999

## CLIQUES - Extensions

- Group certificates
- for use within the group
- for use (meaningful) outside a group
- Non-repudiation of group membership
- opaque, granularity of “any” group member
- strong, granularity of a specific group member
- Non-repudiation to be provided with respect to
- other group members (intra-group)
- outsiders

- DoE NGI PI Meeting, Washington D.C., October 4-5, 1999

## Key Milestones

- Provide security library that supports an integrated API for group key agreement and other services: encryption, integrity, authentication, non-repudiation, etc.
- Define and support policies for authorization of group admission and membership.
- Integrate the security library with a reliable group protocol: Totem (InterGroup?)

- DoE NGI PI Meeting, Washington D.C., October 4-5, 1999

**Notes:**
1. I think this is  mostly  done already.
2 - can each member  add policy? How does a group get defined?

## Requirements for Middleware

- Need Certification Authority and LDAP server.
- Common encryption library - openSSL
- Need underlying reliable group communication with View Synchrony: currently using SPREAD, plan to migrate to ‘hardened’ TOTEM

- DoE NGI PI Meeting, Washington D.C., October 4-5, 1999

**Notes:**
We may be providing these, but it would be useful to decide on a common set.

## Requirements for testbeds

- None anticipated in the first year
- Likely to need a “collaborative” testbed thereafter

- DoE NGI PI Meeting, Washington D.C., October 4-5, 1999

## NGI Big Picture

-   Provide a secure and reliable platform for Next Generation Collaborative Applications

- DoE NGI PI Meeting, Washington D.C., October 4-5, 1999