Secure Multicast Conferencing

Secure multicast conferencing Peter Kirstein, Ian Brown and Edmund Whelan University College London IDC’99, Madrid 23 Sept. 1999 Ian Brown, UCL

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IDC’99, Madrid 23 Sept. 1999 Ian Brown, UCL Multicast conferencing involves... Audio Shared whiteboard

Confidentiality: only authorised conference members can access conference data
Integrity: you can be sure data has not been altered in transit
Authentication: of conference announcers and participants
IDC’99, Madrid 23 Sept. 1999 Ian Brown, UCL Security provides...

Each link is secured using a standard communications security protocol: IPSEC, SSL/TLS, SSH
Extremely wasteful of bandwidth
Multipoint control units are security risks
IDC’99, Madrid 23 Sept. 1999 Ian Brown, UCL Point-to-point conferencing security is easy...

Multicast doesn’t fit the “point-to-point” model of current security protocols
There is no standard method of sharing keys between group members
IDC’99, Madrid 23 Sept. 1999 Ian Brown, UCL But multicast is more tricky...

Use Real-time Transport Protocol (RTP) to send data
Users announce conferences and invite users by sending a session invitation via e-mail, the Session Announcement or Session Invitation Protocols
IDC’99, Madrid 23 Sept. 1999 Ian Brown, UCL Insecure conferences

RTP allows data to be encrypted with DES - implemented in UCL’s tools
We want to move to IPSEC to remove need for cryptographic code in applications and take advantage of its wide range of ciphersuites and protocol and implementation security
IDC’99, Madrid 23 Sept. 1999 Ian Brown, UCL Secure transport

Now standardised by IETF (RFC 2411)
Provides network-layer protection for all packets sent between compatible machines
Not yet finished for multicast
IDC’99, Madrid 23 Sept. 1999 Ian Brown, UCL IP security extensions

The Internet Key Exchange (IKE) allows two hosts to negotiate security parameters for an IPSEC connection
But multicast IKE is much harder, and being investigated by the IRTF
IDC’99, Madrid 23 Sept. 1999 Ian Brown, UCL Key distribution problem

We use secure session invitations to distribute security parameters
Sent using secure SAP, SIP, or e-mail (S/MIME) or retrieved via the World Wide Web (TLS)
IDC’99, Madrid 23 Sept. 1999 Ian Brown, UCL Conferencing solution

Session descriptions are stored on a secure Web server
Authorised conference members can retrieve descriptions over a TLS link
IDC’99, Madrid 23 Sept. 1999 Ian Brown, UCL Web distribution

Users don’t like having to remember many long passphrases
Mobile users need access to keys from many different systems
Software keys are vulnerable to theft
Smartcards alleviate all these problems
IDC’99, Madrid 23 Sept. 1999 Ian Brown, UCL Smartcards

In-network code can reduce bandwidth requirements, convert between coding schemes, provide multicast connectivity, etc. etc.
IDC’99, Madrid 23 Sept. 1999 Ian Brown, UCL Active services

You can give proxies the session keys needed for them to access and process data
We are developing proxies that can work without this security risk
IDC’99, Madrid 23 Sept. 1999 Ian Brown, UCL Processing encrypted data

Multicast conference data can be secured at the network or application layer
Until multicast key distribution is standardised, lightweight methods based on session descriptions can be used
New techniques are needed to allow in-network processing of encrypted data
IDC’99, Madrid 23 Sept. 1999 Ian Brown, UCL Conclusions

Secure Multicast Conferencing

by Ian Brown on Sep 07, 2008

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Secure Multicast Conferencing — Presentation Transcript