2 research outputs found
Secret-Key-Aided Scheme for Securing Untrusted DF Relaying Networks
This paper proposes a new scheme to secure the transmissions in an untrusted
decode-and-forward (DF) relaying network. A legitimate source node, Alice,
sends her data to a legitimate destination node, Bob, with the aid of an
untrusted DF relay node, Charlie. To secure the transmissions from Charlie
during relaying time slots, each data codeword is secured using a secret-key
codeword that has been previously shared between Alice and Bob during the
perfectly secured time slots (i.e., when the channel secrecy rate is positive).
The secret-key bits exchanged between Alice and Bob are stored in a
finite-length buffer and are used to secure data transmission whenever needed.
We model the secret-key buffer as a queueing system and analyze its Markov
chain. Our numerical results show the gains of our proposed scheme relative to
benchmarks. Moreover, the proposed scheme achieves an upper bound on the secure
throughput
Secure Communication Via a Wireless Energy Harvesting Untrusted Relay
The broadcast nature of the wireless medium allows unintended users to
eavesdrop the confidential information transmission. In this regard, we
investigate the problem of secure communication between a source and a
destination via a wireless energy harvesting untrusted node which acts as a
helper to relay the information; however, the source and destination nodes wish
to keep the information confidential from the relay node. To realize the
positive secrecy rate, we use destination-assisted jamming. Being an
energy-starved node, the untrusted relay harvests energy from the received
radio frequency signals, which include the source's information signal and the
destination's jamming signal. Thus, we utilize the jamming signal efficiently
by leveraging it as a useful energy source. At the relay, to enable energy
harvesting and information processing, we adopt power splitting (PS) and time
switching (TS) policies. To evaluate the secrecy performance of this proposed
scenario, we derive analytical expressions for two important metrics, viz., the
secrecy outage probability and the ergodic secrecy rate. The numerical analysis
reveals the design insights into the effects of different system parameters
like power splitting ratio, energy harvesting time, target secrecy rate,
transmit signal-to-noise ratio (SNR), relay location, and energy conversion
efficiency factor, on the secrecy performance. Specifically, the PS policy
achieves better optimal secrecy outage probability and optimal ergodic secrecy
rate than that of the TS policy at higher target secrecy rate and transmit SNR,
respectively.Comment: The paper has been submitted for possible journal publication.
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