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Satellite Networks and Multicast Security

There are several new satellite constellation proposals that support multimedia service traffic. For a successful implementation of such systems, it is essential to address the security requirements of users, satellite network operators and multimedia service providers. I general, satellite communication networks have special security problems for the following reasons:

• Eavesdropping and active intrusion is much easier than in terrestrial fixed or mobile networks because of the broadcast nature of satellites.
• Satellite channels experience high bit error rates which may cause the loss of security synchronization. This demands a careful evaluation of encryption systems to prevent Quality of Service (QoS) degradation because of security processing.
• Satellite networks inherently experience long delays, therefore satellite security systems must be efficient and should only add a minimum delay.

Security may be provided at any level of the protocol stack such as link, network, transport or application layers.  Examples of security services  provided at the satellite link layer are 

• Asynchronous Transfer Mode (ATM) security, see ATM Forum web site for details.
• DVB-S Conditional Access and and DVB-RCS security systems, see ETSI web site.

Secure IP Multicast over Geostationary satellites

The topic of group-oriented security has been researched for over two decades now, particularly in the area of cryptography in the context of secure conferences, secret-sharing and digital multi-signatures, however most of such research has been theoretical only. The Internet, with its rapid growth in multimedia services, can be the media for secure multicasting financial information. The IETF has provided some security standards for the Internet by introducing the Internet security architecture in the IPSec working group and its related technologies, but, they are aimed mainly at unicast transmissions between one sender and one receiver.  Here are three well-known packages that contain open-source IPsec and Internet Key Exchange (IKE) protocol: Kame, OPEN BSD and Free Swan.

Also the Internet community started focusing on secure multicast issues within the MSEC working group. There are several open research issues related to multicast security and group key management such as :

• Trust relations between group members, security server and group owner 
• Security policy definition and enforcement
• Multiple sender authentication
• Denial of service attacks

I worked on and IST project related to secure multicast over satellites called Multicast over Geostationary EHF Satellites (GEOCAST). There is also a need to address multicast security issues over geostationary satellites with on-board routing or switching.    

For more information on satellite security related topics see my publication list.