To resolve the problems in the unconditionally secure secret key agreement model,a new model to obtain the initial random related information was proposed.The experiment results show that compared with existing models,the new model is equivalent in function to the source model and the channel model.However,in the new model,the bit error rate between legal communication parties remains unchanged,while the bit error rate of eavesdropper increases.Hence,the advantage of eavesdropper weakens and the total information key agreement rate increases.
To resolve the problems in the unconditionally secure secret key agreement model,a new model to obtain the initial random related information was proposed.The experiment results show that compared with existing models,the new model is equivalent in function to the source model and the channel model.However,in the new model,the bit error rate between legal communication parties remains unchanged,while the bit error rate of eavesdropper increases.Hence,the advantage of eavesdropper weakens and the total information key agreement rate increases.
Symmetric cryptosystems are very important for secure communication. They are much more efficient then asymmetric cryptosystems. Secret keys are required for symmetric cryptosystems, such as AES. In 2017, Guan and Tzeng designed a secret key establishment protocol whose security depends on the unpredictability of noise in communication channel. They showed that these protocols are secure even if the eavesdropper has infinite computing power. Their protocol works most efficiently for channels with bit-flip rate around 0.01. For the case when bit-flip rate is much smaller than 0.01, their protocol needs a long random bit string to accumulate enough uncertainty to establish a secret key. In this article, an improved protocol for establishing secret key is proposed. The new method requires much less random bits for channels with small bit-flip rates, such as in the range [0.001, 0.010]. With the improvement of wireless communication technology, the bit-flip rate is reducing. Therefore, the new method is suitable for the current wireless networks technology.
We study the problem of information-theoretically secure secret key agreement under the well-known source model and channel model. In both of these models the parties wish to create a shared secret key that is secure from an eavesdropper with unlimited computational resources. In the channel model, the first party can choose a sequence of inputs to a discrete memoryless channel, which has outputs at the other parties and at the eavesdropper. After each channel use, the parties can engage in arbitrarily many rounds of interactive authenticated communication over a public channel. At the end, each party should be able to generate the key. In the source model, the parties wishing to generate a secret key (as well as the eavesdropper) receive a certain number of independent identically distributed copies of jointly distributed random variables after which the parties are allowed interactive authenticated public communication, at the end of which each party should be able to generate the key. We derive new lower and upper bounds on the secret key rate under the source model and the channel model, and introduce a technique for proving that a given expression bounds the secrecy rate from above in the channel model. Our lower bounds strictly improve what is essentially the best known lower bound in both the source model and the channel model. Our upper bound in the channel model strictly improves the current state of art upper bound. We do not know whether our new upper bound in the source model represents an strict improvement but it includes the current best known bound as a special case.
An efficient protocol for establishing secret keys for neighboring nodes in a wireless network is presented in this paper. The security of the key generated by our protocol is based on the unpredictability of the noises in binary symmetric communication channels. The two nodes which try to establish a common secret key receive messages from a common source of random bit strings. Due to noises in the communication channel, the messages received by them, and most importantly the messages received by the eavesdropper, are not the same. We show that the two nodes can modify their messages in an efficient way to obtain a common string which contains enough uncertainty to the eavesdropper. Then, a secure universal hash function is applied to compute a secret key for extracting randomness from the common string. We prove that the probability for the eavesdropper to know the value of the key is negligible. One advantage of our proposed protocol is that the secret key rate is better than the known scheme in other models, such as the bounded storage model. Furthermore, our proposed protocol needs only to perform exclusive-or operations and compute hash values. Thus, it is a computationally light-weight protocol and suitable for devices with limited computing resources, such as sensors in sensor networks.
We study the problem of information-theoretically secure secret key agreement under the well-known source model and channel model. In both of these models, multiple terminals wish to create a shared secret key that is secure from a passive eavesdropper. The terminals have access to a noiseless public communication channel and an additional resource that depends on the model. In the source model, the resource is an external source that repeatedly beams correlated randomness to the terminals; whereas in the channel model, the resource is a secure but noisy discrete memoryless broadcast channel. We derive new lower and upper bounds on the secret key capacity under both the source model and the channel model. The technique used for deriving our bound for the source model is to find certain properties of functions of joint probability distributions which, applied to the joint distribution of the source, will imply that they dominate the secret key capacity, and then prove the bound by a verification argument. A similar technique is used for the channel model. Finally, we also define a problem of communication for omniscience by a neutral observer and establish the equivalence between this new problem and the problem of secret key agreement. This generalizes an earlier result of Csiszár and Narayan.
The applications of Wireless Sensor Networks (WSNs) are widespread in areas such as environmental monitoring, industrial automation, healthcare and smart infrastructures, where secure and reliable wireless communication is essential. The nature of a wireless channel, however, lends itself to the problem of eavesdropper-directed wireless sensor networking, interception and unauthorized access. This paper presents a secure physical layer communication system featuring the combination of channel estimator, physical layer key generator, artificial noise generator and adaptive power allocator to increase the confidentiality of physical layer communications and simultaneously achieve energy efficiency. A hybrid security mechanism is used, which takes advantage of the channel characteristics to create secret keys and to make the eavesdropper's signal reception worse by introducing controlled artificial noise. Key performance parameters considered for simulation-based evaluation are secrecy capacity, BER, PDR, Throughput, Energy consumption and Network lifetime. Results show that the secrecy capacity is 6.3 bps/Hz, the packet delivery ratio is 98.7%, the bit error rate is 10⁻⁶, and the network lifetime is 1675 rounds. The proposed framework is much more effective in terms of both communication security and energy efficiency than the traditional WSNs security schemes.
Computationally lightweight and unconditionally secure key agreement protocols are very useful for secure communication in public networks. Recently, Guan et al. proposed a key agreement protocol whose security is based on the unpredictability of channel noise rather than computationally hard problems. These protocols are efficient, computationally lightweight, and unconditionally secure. However, authentication was not integrated into these protocols. In this article, we propose a new protocol with authentication capability that enables two nodes in the network to establish a secret session key for secure communication. It is more efficient, and it also preserves the lightweight and unconditional secure features of the key agreement protocols proposed by Guan et al. Therefore, it is more suitable for devices with limited computing power, such as sensors in Internet of Things (IoT).