Yanling Chen

Wiretap Channel With Side Information

This correspondence gives an achievable rate equivocation region for the discrete memoryless wiretap channel with side information. We extend our results to the Gaussian case. The main contribution of this correspondence is that, for the Gaussian wiretap channel, the side information helps to get a larger secrecy capacity and a larger rate equivocation region.

Wiretap channel with side information

This paper gives a rate equivocation achievable region for the discrete memoryless wiretap channel with side information. The secrecy capacities in some special cases are also determined. We extend our result to the Gaussian case. It is very interesting to find that, for the wiretap channel, unlike the dirty paper channel, the side information helps to get larger secrecy capacity . Moreover, the rate equivocation region is also larger than that of the Gaussian wiretap channel where the side information is absent.

On the individual secrecy rate region for the broadcast channel with an external eavesdropper

This paper studies the problem of secure communication over broadcast channels under the lens of individual secrecy constraints (i.e., information leakage from each message to an eavesdropper is made vanishing). It is known that, for the communication over the degraded broadcast channels, the stronger receiver is able to decode the message of the weaker receiver. In the individual secrecy setting, the message for the weaker receiver can be further utilized to secure the partial message that is intended to the stronger receiver. With such a coding spirit, it is shown that more secret bits can be conveyed to the stronger receiver. In particular, for the corresponding Gaussian model, a constant gap (i.e., 0.5 bits within the individual secrecy capacity region) result is obtained. Overall, when compared with the joint secrecy constraint, the results allow for trading-off secrecy level and throughput in the system.

On the achievable individual-secrecy rate region for broadcast channels with receiver side information

In this paper, we study the problem of secure communication over the broadcast channel with receiver side information, under the lens of individual secrecy constraints (i.e., information leakage from each message to an eavesdropper is made vanishing). Several coding schemes are proposed by extending known results in broadcast channels to this secrecy setting. In particular, individual secrecy provided via one-time pad signal is utilized in the coding schemes. As a result, we obtain an achievable rate region together with a characterization of the capacity region for special cases of either a weak or strong eavesdropper (compared to both legitimate receivers). Interestingly, the capacity region for the former corresponds to a line and the latter corresponds to a square with missing corners; a phenomenon occurring due to the coupling between users rates. At the expense of having a weaker notion of security, positive secure transmission rates are always guaranteed, unlike the case of the joint secrecy constraint.

Individual Secrecy for Broadcast Channels With Receiver Side Information

This paper studies the problem of secure communication over the broadcast channel with receiver-side information under the lens of individual secrecy constraints, that is, the transmitter wants to send two independent messages to two receivers, which have, respectively, the desired message of the other receiver as side information, while keeping the eavesdropper ignorant of each message (i.e., the information leakage rate from each message to the eavesdropper is made vanishing). Building upon one-time pad, secrecy coding, and broadcasting schemes, achievable rate regions are investigated, and the capacity region for special cases of either a weak or strong eavesdropper (compared to both legitimate receivers) is characterized. Interestingly, the capacity region for the former corresponds to a line and the latter corresponds to a rectangle with missing corners; a phenomenon occurring due to the coupling between user’s rates. Moreover, the individual secrecy capacity region is also fully characterized for the case where the eavesdropper’s channel is deterministic. In addition to discrete memoryless setup, Gaussian scenarios are studied. For the Gaussian model, in addition to the strong and weak eavesdropper cases, the capacity region is characterized for the low and high SNR regimes when the eavesdropper’s channel is stronger than one receiver but weaker than the other. Remarkably, positive secure transmission rates are always guaranteed under the individual secrecy constraint, unlike the case of the joint secrecy constraint (i.e., the information leakage rate from both messages to the eavesdropper is made vanishing). Thus, this notion of secrecy serves as an appropriate candidate for trading off secrecy level and transmission rate, making secrecy more affordable but still acceptable to the end user.

On the individual secrecy for Gaussian broadcast channels with receiver side information

This paper studies the individual secrecy capacity region of the broadcast channel with receiver side information. First, an achievable rate region is established for the discrete memoryless case by employing superposition coding. Further, it is extended to the corresponding Gaussian case, where the individual secrecy capacity region is characterized in case of a weak or strong eavesdropper (compared to two legitimate receivers). For the case left, inner and outer bounds are established and the individual secrecy capacity region is characterized for the low and high SNR regimes. Note that the last case is distinctive due to the individual secrecy constraint, in the sense that positive rate pair is still possible although the eavesdropper may have the advantage against at least one of the legitimate receivers over the channel, unlike the situation if the joint secrecy constraint is imposed.

On some properties of a check digit system

In this paper, we consider check digit systems which are based on the use of elementary abelian p-groups of order pk. The work is inspired by a recently introduced check digit system for hexadecimal numbers. By interpreting its check equation in terminology of matrix algebra, we generalize the idea to build systems over a group of order pk, while keeping the ability to detect all the 1) single errors, 2) adjacent transpositions, 3) twin errors, 4) jump transpositions and 5) jump twin errors. Besides, we consider two categories of jump errors: t-jump transpositions and t-jump twin errors, which include and further extend the double error types of 2)-5). In particular, we explore the capacity range of the system to detect these two kinds of generalized jump errors, and demonstrate that it is 2k - 3 for p = 2 and (pk -1)/2-2 for an odd prime p. Also, we show how to build such a system that detects all the single errors and these two kinds of double jump-errors within the capacity range.

Construction of Multivariate Quadratic Quasigroups (MQQs) in arbitrary Galois fields

In this paper we describe two methods for constructing Multivariate Quadratic Quasigroups (MQQ) in Galois fields of any characteristic and order. Our constructions extend the previously known constructions defined for operations over the prime field of characteristic 2. Application of these new constructions can reduce the public key size of the recently introduced family of public key schemes based on MQQs up to 58 times.

Wiretap Channel with Correlated Sources

This paper studies the problem of secret-message transmission over a wiretap channel with correlated sources in the presence of an eavesdropper who has no source observation. A coding scheme is proposed based on a careful combination of 1) Wyner-Zivs source coding to generate secret key from correlated sources based on a certain cost on the channel, 2) one-time pad to secure messages without additional cost, and 3) Wyners secrecy coding to achieve secrecy based on the advantage of legitimate receivers channel over the eavesdroppers. The work sheds light on optimal strategies for practical code design for secure communication/storage systems.

Individual Secrecy for the Broadcast Channel

This paper studies the problem of secure communications over broadcast channels under the individual secrecy constraints. That is, the transmitter wants to send two independent messages to two legitimate receivers in the presence of an eavesdropper, while keeping the eavesdropper ignorant of each message (i.e., the information leakage rate from each message to the eavesdropper is made vanishing). Building upon Carleial–Hellman’s secrecy coding, Wyner’s secrecy coding, and the framework of Marton’s coding together with techniques, such as rate splitting and indirect decoding, an achievable individual secrecy rate region is established with the characterization of capacity regions for some special cases. In particular, the individual secrecy capacity region for the linear deterministic model is fully characterized, and for the Gaussian model, a constant gap (i.e., 0.5 b within the individual secrecy capacity region) result is obtained. To illustrate the impact of different secrecy constraints on the corresponding capacity regions, comparisons are made with those satisfying joint secrecy and without secrecy constraints. Overall, when compared with the joint secrecy constraint, the results allow for trading off secrecy level and throughput in the system.