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Chapter 8: Summary, Conclusion, and Future Works 111
defined in terms of generalized weak security in our work. Since weak security is also
inherent in secure network coding, it follows that secure network coding possesses USP
capability as well.
Secure network coding is a class of network coding used for cryptographic purposes.
The earlier purpose of network coding is to facilitate multicast transmission. Although
both deterministic and random network coding can improve the multicast rate, only deterministic
network coding can guarantee max-flow transmission. Another advantage of
deterministic network coding is that we are better in control of the unequal-erasureprotection
(UEP) capability, as discussed in Chapter 4. This UEP property can lead to
conflicts among the multicast receivers in terms of received data quality. When the conflicts
are considered as economic problems of resource distribution, an auction algorithm
can be used to resolve them, as proposed in Chapter 4. If they are considered as political
problems, a voting algorithm could be an interesting solution.
In practice, network coding will probably be used in a system in which channel coding
is present. A problem occurs when the channel coding performance depends on the degree
distribution of the codes, which may be affected by network coding and erasures in the
network. A particular problem in LT-codes is discussed in Chapter 5 and a cooperative
buffering scheme is proposed as a solution.
In conclusion, this thesis highlights several interrelationships among several subjects in
the fields of coding and cryptography. We pictorially summarize it in Fig. 8.1. Apart from
this, network protocol aspects are also considered for WPSG in generalized networks in
Chapter 6, showing that network coding can enhance the security of the WPSG protocol.
8.2 Future Works
In the following, we shortly address some possibilities for future research.