For secure communication, we need random cryptographic keys. However, the sensor node which is slow processing device which is not able to perform the operations those generates a complex public key. Also, they cannot generate the good random number generator which is useful for key generation. This problem is solved by doing the measurements of per-packet signal strength which helps us to generate secret keys. The packet strength of another device as one of the sources of randomness is received using this generator. We can also use as a bidirectional synchronized transmission of constant bit rate (CBR) between two parties. Here one device stand on the surface and other devices moves around it. The each device can receive the result of source of randomness from the per-packet power. It also provides security from a third party. A third party cannot extract the information from the per-packet signal measurement generated by any devices if, it is not located near any transceiver's location or standing devices. Here results of the solution in network simulator NS-2 also present.
For secure communication, we need random cryptographic keys. However, the sensor node which is slow processing device which is not able to perform the operations those generates a complex public key. Also, they cannot generate the good random number generator which is useful for key generation. This problem is solved by doing the measurements of per-packet signal strength which helps us to generate secret keys. The packet strength of another device as one of the sources of randomness is received using this generator. We can also use as a bidirectional synchronized transmission of constant bit rate (CBR) between two parties. Here one device stand on the surface and other devices moves around it. The each device can receive the result of source of randomness from the per-packet power. It also provides security from a third party. A third party cannot extract the information from the per-packet signal measurement generated by any devices if, it is not located near any transceiver's location or standing devices. Here results of the solution in network simulator NS-2 also present.
We evaluate the effectiveness of secret key extraction, for private communication between two wireless devices, from the received signal strength (RSS) variations on the wireless channel between the two devices. We use real world measurements of RSS in a variety of environments and settings. The results from our experiments with 802.11-based laptops show that in certain environments, due to lack of variations in the wireless channel, the extracted bits have very low entropy making these bits unsuitable for a secret key, an adversary can cause predictable key generation in these static environments, and in dynamic scenarios where the two devices are mobile, and/or where there is a significant movement in the environment, high entropy bits are obtained fairly quickly. Building on the strengths of existing secret key extraction approaches, we develop an environment adaptive secret key generation scheme that uses an adaptive lossy quantizer in conjunction with Cascade-based information reconciliation and privacy amplification. Our measurements show that our scheme, in comparison to the existing ones that we evaluate, performs the best in terms of generating high entropy bits at a high bit rate. The secret key bit streams generated by our scheme also pass the randomness tests of the NIST test suite that we conduct. We also build and evaluate the performance of secret key extraction using small, low-power, hand-held devices-Google Nexus One phones-that are equipped 802.11 wireless network cards. Last, we evaluate secret key extraction in a multiple input multiple output (MIMO)-like sensor network testbed that we create using multiple TelosB sensor nodes. We find that our MIMO-like sensor environment produces prohibitively high bit mismatch, which we address using an iterative distillation stage that we add to the key extraction process. Ultimately, we show that the secret key generation rate is increased when multiple sensors are involved in the key extraction process.
In this paper, we evaluate the effectiveness of secret key extraction from the Received signal strength (RSS) variations on the wireless channel between the two devices for private communication between them. We use real world measurements of RSS in a variety of environments and settings. The results from our experiments with 802.11-based laptops show that 1)An adversary can cause predictable key generation in these static environments, and 2)In dynamic scenarios where the two devices are mobile, high entropy bits are obtained . Building on the strengths of existing secret key extraction approaches, we develop an environment adaptive secret key generation scheme that uses an adaptive Cascade-based information reconciliation and privacy amplification. In our scheme, to provide good scalability in terms of the number of nodes, we utilize a combinatorial design of public-private key pairs, which means nodes combine more than one key pair to encrypt and decrypt messages. We also show that it provides controllable resilience when malicious nodes compromise a limited number of nodes before key revocation and renewal.
We evaluate the effectiveness of secret key extraction, for private communication between two wireless devices, from the received signal strength (RSS) variations on the wireless channel between the two devices. We use real world measurements of RSS in a variety of environments and settings. Our experimental results show that (i) in certain environments, due to lack of variations in the wireless channel, the extracted bits have very low entropy making these bits unsuitable for a secret key, (ii) an adversary can cause predictable key generation in these static environments, and (iii) in dynamic scenarios where the two devices are mobile, and/or where there is a significant movement in the environment, high entropy bits are obtained fairly quickly. Building on the strengths of existing secret key extraction approaches, we develop an environment adaptive secret key generation scheme that uses an adaptive lossy quantizer in conjunction with Cascade-based information reconciliation [7] and privacy amplification [14]. Our measurements show that our scheme, in comparison to the existing ones that we evaluate, performs the best in terms of generating high entropy bits at a high bit rate. The secret key bit streams generated by our scheme also pass the randomness tests of the NIST test suite [21] that we conduct.
In symmetric cryptography systems have problems in the distribution of secret keys. The two users who will communicate require sharing keys through the public channel. The proposed solution to overcome these problems is to utilize information from the physical layer (e.g. RSS). Received Signal Strength (RSS) is an indicator for measuring the power received by wireless devices. The advantage of secret key extraction using physical layer information from a wireless channel is that it allows both devices within the transmission range to extract the secret key together. In this paper, we propose a secret key generation scheme adopted from an existing scheme with modifications to improve performance. Our proposed system is applied to static and dynamic conditions to test performance. The proposed algorithm is able to obtain a reduction in KDR (Key Disagreement Rate) up to 48.42% and an increase in the KGR (Key Generation Rate) up to 23.35% when compared to the existing scheme. Our proposed system also successfully passed the randomness using the NIST test with the approximate value of entropy generated 0.80 in static conditions and 0.81 in dynamic conditions.
Due to the broadcast nature of wireless channels, wireless communication is vulnerable to eavesdropping, message modification, and node impersonation. Securing the wireless communication requires the shared secret keys between the communicating entities. Traditional security schemes rely on public key infrastructures and cryptographic algorithms to manage secret keys. Recently, many physical-layer-based methods have been proposed as alternative solutions for key generation in wireless networks. These methods exploit the inherent randomness of the wireless fading channel to generate secret keys while providing information-theoretical security without intensive cryptographic computations. This article provides an overview of the existing PHY-based key generation schemes exploiting the randomness of the wireless channels. Specifically, we first introduce the fundamental and general framework of the PHY-based key generation schemes and then categorize them into two classes: received-signal-strength-based and channel- phase-based protocols. Finally, we present a performance comparison of them in terms of key disagreement probability, key generation rate, key bit randomness, scalability, and implementation issues.
Secret key establishment is a fundamental requirement for private communication between two entities. In this article, we propose and evaluate a new approach for secret key extraction where multiple sensors collaborate in exchanging probe packets and collecting channel measurements. Essentially, measurements from multiple channels have a substantially higher differential entropy compared to the measurements from a single channel, thereby resulting in more randomness in the information source for key extraction, and this in turn produces stronger secret keys. We also explore the fundamental trade-off between the quadratic increase in the number of measurements of the channels due to multiple nodes per group versus a linear reduction in the sampling rate and a linear increase in the time gap between bidirectional measurements. To experimentally evaluate collaborative secret key extraction in wireless sensor networks, we first build a simple yet flexible testbed with multiple TelosB sensor nodes. Next, we perform large-scale experiments with different configurations of collaboration. Our experiments show that in comparison to the 1 × 1 configuration, collaboration among sensor nodes significantly increases the secret bit extraction per second, per probe, as well as per millijoule of transmission energy. In addition, we show that the collaborating nodes can improve the performance further when they exploit both space and frequency diversities.