New book: "Information Theory, Combinatorics, and Search Theory"

In Memory of Rudolf Ahlswede

A festschrift will be published by Harout Aydinian, Ferdinando Cicalese and Christian Deppe (Eds.) in the series, “Lecture Notes in Computer Science” to commemorate Rudolf Ahlswede for his profound work in information theory, combinatorics, and search methodologies. 
Rudolf Ahlswede made many fundamental contributions in the field of information theory.  Among his publications were research articles on the capacity of arbitrarily varying channels, information theoretic security, multiuser information theory, quantum information theory, and zero error capacity. In its three papers, the Institute pays tribute to Rudolf Ahlswede and endeavors to continue his research.

  • Moritz Wiese and Holger Boche
    Strong Secrecy for Multiple Access Channels, H. Aydinian, F. Cicalese, and C. Deppe (Eds.), Ahlswede Festschrift, LNCS 7777, 71-122, 2013.
    ABSTRACT: We show strongly secret achievable rate regions for two different wiretap multiple-access channel coding problems. In the first problem, each encoder has a private message and both togehter have a common message to transmit. The encoders have entropy-limited access to common radnomness. If no common randomness is available, then the achievable region derived here does not allow for the secret transmission of a common message and common message. The second coding problem assumes that the encoders do not have a common message nor access to common randomness. However, they may have a conferencing link over which they may iteratively exchange rate-limited information. This can be used to form a common message and common randomness to reduce the second coding problem to the first one. We give the example of a channel where the achievable region equals zero without conferencing or common randomness and where conferencing establishes the possibility of secret message transmission. Both coding problems describe practically relevant networks which need to be secured eavesdropping attacks.
  • Igor Bjelakovic, Holger Boche, and Jochen Sommerfeld
    Capacity Results for Arbitrarily Varying Wiretap Channels, H. Aydinian, F. Cicalese, and C. Deppe (Eds.), Ahlswede Festschrift, LNCS 7777, 123-144, 2013.
    ABSTRACT: In this work the arbitrarily varying wiretap channel AVWC is studied. We derive a lower bound on the random code secrecy capacity for the average error criterion and the strong secrecy criterion in the case of a best channel to the eavesdropper by using Ahlswede's robusttification technique for ordinary AVCs. We show that in the case of a non-symmetrisable channel to the legitimate receiver the deterministic code secrecy capacity equals the random code secrecy capacity, a result similar to Ahlswede's dichotomy result for ordinary AVCs. Using this we can derive that the lower bound is also valid for the deterministic code capacity of the AVWC. The proof of the dichotomy result is based on the elimination technique introduced by Ahlswede for ordinary AVCs. We further prove upper bounds on the deterministic code secrecy capacity in the general case, which results in a mullti-letter expression for the secrecy capacity in the case of a best channel to the eavesdropper. Using techniques of Ahlswede, developed to guarantee the validity of a reliable criterion, the main contribution of this work is to intergrate the strong secrecy criterion into these techniques.
  • Igor Bjelakovic, Holger Boche, Gisbert Janßen, and Janis Nötzel
    Arbitrarily Varying and Compound Classical-Quantum Channels and a Note on Quantum Zero-Error Capacities, H. Aydinian, F. Cicalese, and C. Deppe (Eds.), Ahlswede Festschrift, LNCS 7777, 247-283, 2013.
    ABSTRACT: We consider compound as well as arbitrarily varying classical-quantum channel models. For classical-quantum compound channels, we give an elementary proof of the direct part of the coding theorem. A weak converse under average error criterion to this statement is also established. We use this result together with the robustification and elimination technique developed by Ahlswede in order to give an alternative proof of the direct part of the coding theorem for a finite classical-quantum arbitraliy varying channels with the criterion of success being average error probability. Moreover we provide a proof of the strong converse to the random coding capacity in this setting. The notion of symmetrization for the maximal error probability is defined and it is shown to be both necessary and sufficient for the capacity for message transmission with maximal error probability criterion to equal zero. Finally, it is shown that the connection between zero-error capacity and certain arbitrarily varying channels is, just like in the case of quantum channels, only partially valid for classical-quantum channels.