Efficient reliable communication over partially authenticated networks

Amos Beimel, Lior Malka

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Reliable communication between processors in a network is a basic requirement for executing any protocol. Dolev [7] and Dolev et al. [8] showed that reliable communication is possible if and only if the communication network is sufficiently connected. Beimel and Franklin [1] showed that the connectivity requirement can be relaxed if some pairs of processors share authentication keys. That is, costly communication channels can be replaced by authentication keys. In this work, we continue this line of research. We consider the scenario where there is a specific sender and a specific receiver in a synchronous network. In this case, the protocol of [1] has n O(n) rounds even if there is a single Byzantine processor. We present a more efficient protocol with round complexity of (n/t) O(t), where n is the number of processors in the network and t is an upper bound on the number of Byzantine processors in the network. Specifically, our protocol is polynomial when the number of Byzantine processors is O(1), and for every t its round complexity is bounded by 2 O(n). The same improvements hold for reliable and private communication. The improved protocol is obtained by analyzing the properties of a "communication and authentication graph" that characterizes reliable communication.

Original languageEnglish
Pages (from-to)1-19
Number of pages19
JournalDistributed Computing
Issue number1
StatePublished - 1 Jul 2005


  • Authentication
  • Fault tolerance
  • Incomplete networks
  • Reliable communication

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Hardware and Architecture
  • Computer Networks and Communications
  • Computational Theory and Mathematics


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