In this paper, we study the degraded multiple-access channel (MAC) with confidential messages, where two users transmit their confidential messages (no common message) to a destination, and each user obtains a degraded version of the output of the MAC. Each user views the other user as a eavesdropper, and wishes to keep its confidential message as secret as possible from the other user. Measuring each users uncertainty about the other users confidential message by equivocation, the inner and outer bounds on the capacity equivocation region for this model have been provided. The result is further explained via the binary and Gaussian examples.
In this paper, we study the degraded multiple-access channel (MAC) with confidential messages, where two users transmit their confidential messages (no common message) to a destination, and each user obtains a degraded version of the output of the MAC. Each user views the other user as a eavesdropper, and wishes to keep its confidential message as secret as possible from the other user. Measuring each users uncertainty about the other users confidential message by equivocation, the inner and outer bounds on the capacity equivocation region for this model have been provided. The result is further explained via the binary and Gaussian examples.
Several security models of multiple-access channel (MAC) are investigated. First, we study the degraded MAC with confidential messages, where two users transmit their confidential messages (no common message) to a destination, and each user obtains a degraded version of the output of the MAC. Each user views the other user as a eavesdropper, and wishes to keep its confidential message as secret as possible from the other user. Measuring each user's uncertainty about the other user's confidential message by equivocation, the inner and outer bounds on the capacity-equivocation region for this model have been provided. The result is further explained via the binary and Gaussian examples. Second, the discrete memoryless multiple-access wiretap channel (MAC-WT) is studied, where two users transmit their corresponding confidential messages (no common message) to a legitimate receiver, while an additional wiretapper wishes to obtain the messages via a wiretap channel. This new model is considered into two cases: the general MAC-WT with cooperative encoders, and the degraded MAC-WT with non-cooperative encoders. The capacity-equivocation region is totally determined for the cooperative case, and inner and outer bounds on the capacity-equivocation region are provided for the non-cooperative case. For both cases, the results are further explained via the binary examples.
A discrete memoryless multiple-access channel (MAC) with confidential messages is studied, where two users attempt to transmit common information to a destination and each user also has private (confidential) information intended for the destination. This channel generalizes the classical MAC model in that each user also receives channel outputs, and hence may obtain the confidential information sent by the other user from the channel output it receives. However, each user views the other user as a wiretapper or eavesdropper, and wishes to keep its confidential information as secret as possible from the other user. The level of secrecy of the confidential information is measured by the equivocation rate, i.e., the entropy rate of the confidential information conditioned on channel outputs at the wiretapper (the other user). The performance measure is the rate-equivocation tuple that includes the common rate, two private rates, and two equivocation rates as components. The set that includes all achievable rate-equivocation tuples is referred to as the capacity-equivocation region. The case of perfect secrecy is particularly of interest, in which each user's confidential information is perfectly hidden from the other user. The set that includes all achievable rates with perfect secrecy is referred to as the secrecy capacity region. For the MAC with two confidential messages, in which both users have confidential messages for the destination, inner bounds on the capacity-equivocation region, and secrecy capacity region are obtained. It is demonstrated that there is a tradeoff between the two equivocation rates (secrecy levels) achieved for the two confidential messages. For the MAC with one confidential message, in which only one user (user 1) has private (confidential) information for the destination, inner and outer bounds on the capacity-equivocation region are derived. These bounds match partially, and hence the capacity-equivocation region is partially characterized. Furthermore, the outer bound provides a tight converse for the case of perfect secrecy, and hence establishes the secrecy capacity region. A class of degraded MACs with one confidential message is further studied, and the capacity-equivocation region and the secrecy capacity region are established. These results are further explored via two example channels: the binary and Gaussian MACs. For both channels, the capacity-equivocation regions and the secrecy capacity regions are obtained.
A discrete memoryless generalized multiple access channel (GMAC) with confidential messages is studied, where two users attempt to transmit common information to a destination and each user also has private (confidential) information intended for the destination. This channel generalizes the multiple access channel (MAC) in that the two users also receive channel output. It is assumed that each user views the other user as a wiretapper, and wishes to keep its confidential information as secret as possible from the other user. The level of secrecy of the confidential information is measured by the equivocation rate. The performance measure of interest is the rate-equivocation tuple that includes the common rate, two private rates and two equivocation rates as components. The set that includes all achievable rate-equivocation tuples is referred to as the capacity-equivocation region. For the GMAC with one confidential message set, where only one user (user 1) has private (confidential) information for the destination, inner and outer bounds on the capacity-equivocation region are derived. The outer bound provides a tight converse to the secrecy capacity region, which is the set of all achievable rates with user 2 being perfectly ignorant of confidential messages of user 1, thus establishing the secrecy capacity region. Furthermore, the degraded GMAC with one confidential message set is further studied, and the capacity-equivocation region and the secrecy capacity region are established. For the GMAC with two confidential message sets, where both users have confidential messages for the destination, an inner bound on the capacity-equivocation region is obtained. The secrecy rate region is derived, where each user's confidential information is perfectly hidden from the other user
A discrete memoryless generalized multiple access channel (GMAC) with confidential messages is studied, where two users attempt to transmit common information to a destination and each user also has private (confidential) information intended for the destination. This channel generalizes the multiple access channel (MAC) in that the two users also receive channel outputs. It is assumed that each user views the other user as a wire-tapper, and wishes to keep its confidential information as secret as possible from the other user. The level of secrecy of the confidential information is measured by the equivocation rate. The performance measure of interest is the rate-equivocation tuple that includes the common rate, two private rates and two equivocation rates as components. The set that includes all achievable rate-equivocation tuples is referred to as the capacity-equivocation region. For the GMAC with one confidential message set, where only one user (user 1) has private (confidential) information for the destination, inner and outer bounds on the capacity-equivocation region are derived. The secrecy capacity region is established, which is the set of all achievable rates with user 2 being perfectly ignorant of confidential messages of user 1. Furthermore, the capacity-equivocation region and the secrecy capacity region are established for the degraded GMAC with one confidential message set. For the GMAC with two confidential message sets, where both users have confidential messages for the destination, inner bounds on the capacity-equivocation region and the secrecy capacity region are obtained.
The fading cognitive multiple-access channel with confidential messages (MAC-CM) is investigated, in which two users attempt to transmit common information to a destination and user 1 also has confidential information intended for the destination. User 1 views user 2 as an eavesdropper and wishes to keep its confidential information as secret as possible from user 2. The multiple-access channel (both the user-to-user channel and the user-to-destination channel) is corrupted by multiplicative fading gain coefficients in addition to additive white Gaussian noise. The channel state information (CSI) is assumed to be known at both the users and the destination. A parallel MAC-CM with independent subchannels is first studied. The secrecy capacity region of the parallel MAC-CM is established, which gives the secrecy capacity region of the parallel MAC-CM with degraded subchannels. Next, the secrecy capacity region is established for the parallel Gaussian MAC-CM, which is used to study the fading MAC-CM. By assuming both users know the CSI, users can dynamically change their transmission power with the channel realization to achieve the best performance.
A generalized multiple access channel (GMAC) with one confidential message set is studied, where two users (users 1 and 2) attempt to transmit common information to a destination, and user 1 also has confidential information intended for the destination. Moreover, user 1 wishes to keep its confidential information as secret as possible from user 2. A deterministic GMAC is first studied, and the capacity-equivocation region and the secrecy capacity region are obtained. Two main classes of the GMAC are then studied: the binary GMAC and the Gaussian GMAC. For both channels, the capacity-equivocation region and the secrecy capacity region are established.