A survey of security issues in wireless sensor networks <s>  <s> In the near future, many personal electronic devices will be able to communicate with each other over a short range wireless channel. We investigate the principal security issues for such an environment. Our discussion is based on the concrete example of a thermometer that makes its readings available to other nodes over the air. Some lessons learned from this example appear to be quite general to ad-hoc networks, and rather different from what we have come to expect in more conventional systems: denial of service, the goals of authentication, and the problems of naming all need re-examination. We present the resurrecting duckling security policy model, which describes secure transient association of a device with multiple serialised owners. <s> BIB001 </s> A survey of security issues in wireless sensor networks <s>  <s> As sensor networks edge closer towards wide-spread deployment, security issues become a central concern. So far, much research has focused on making sensor networks feasible and useful, and has not concentrated on security. We present a suite of security building blocks optimized for resource-constrained environments and wireless communication. SPINS has two secure building blocks: SNEP and μTESLA SNEP provides the following important baseline security primitives: Data confidentiality, two-party data authentication, and data freshness. A particularly hard problem is to provide efficient broadcast authentication, which is an important mechanism for sensor networks. μTESLA is a new protocol which provides authenticated broadcast for severely resource-constrained environments. We implemented the above protocols, and show that they are practical even on minimal hardware: the performance of the protocol suite easily matches the data rate of our network. Additionally, we demonstrate that the suite can be used for building higher level protocols. <s> BIB002 </s> A survey of security issues in wireless sensor networks <s>  <s> An emerging class of important applications uses ad hoc wireless networks of low-power sensor devices to monitor and send information about a possibly hostile environment to a powerful base station connected to a wired network. To conserve power, intermediate network nodes should aggregate results from individual sensors. However, this opens the risk that a single compromised sensor device can render the network useless, or worse, mislead the operator into trusting a false reading. We present a protocol that provides a secure aggregation mechanism for wireless networks that is resilient to both intruder devices and single device key compromises. Our protocol is designed to work within the computation, memory and power consumption limits of inexpensive sensor devices, but takes advantage of the properties of wireless networking, as well as the power asymmetry between the devices and the base station. <s> BIB003 </s> A survey of security issues in wireless sensor networks <s>  <s> Strong public-key cryptography is often considered to be too computationally expensive for small devices if not accelerated by cryptographic hardware. We revisited this statement and implemented elliptic curve point multiplication for 160-bit, 192-bit, and 224-bit NIST/SECG curves over GF(p) and RSA-1024 and RSA-2048 on two 8-bit microcontrollers. To accelerate multiple-precision multiplication, we propose a new algorithm to reduce the number of memory accesses. <s> BIB004 </s> A survey of security issues in wireless sensor networks <s>  <s> Sensor networks are often deployed in unattended environments, thus leaving these networks vulnerable to false data injection attacks in which an adversary injects false data into the network with the goal of deceiving the base station or depleting the resources of the relaying nodes. Standard authentication mechanisms cannot prevent this attack if the adversary has compromised one or a small number of sensor nodes. In this paper, we present an interleaved hop-by-hop authentication scheme that guarantees that the base station will detect any injected false data packets when no more than a certain number t nodes are compromised. Further, our scheme provides an upper bound B for the number of hops that a false data packet could be forwarded before it is detected and dropped, given that there are up to t colluding compromised nodes. We show that in the worst case B is O(t/sup 2/). Through performance analysis, we show that our scheme is efficient with respect to the security it provides, and it also allows a tradeoff between security and performance. <s> BIB005 </s> A survey of security issues in wireless sensor networks <s>  <s> In this paper, we quantify the energy cost of authentication and key exchange based on public-key cryptography on an 8-bit microcontroller platform. We present a comparison of two public-key algorithms, RSA and elliptic curve cryptography (ECC), and consider mutual authentication and key exchange between two untrusted parties such as two nodes in a wireless sensor network. Our measurements on an Atmel ATmega128L low-power microcontroller indicate that public-key cryptography is very viable on 8-bit energy-constrained platforms even if implemented in software. We found ECC to have a significant advantage over RSA as it reduces computation time and also the amount of data transmitted and stored. <s> BIB006 </s> A survey of security issues in wireless sensor networks <s>  <s> In sensor networks, data aggregation is a vital primitive enabling efficient data queries. An on-site aggregator device collects data from sensor nodes and produces a condensed summary which is forwarded to the off-site querier, thus reducing the communication cost of the query. Since the aggregator is on-site, it is vulnerable to physical compromise attacks. A compromised aggregator may report false aggregation results. Hence, it is essential that techniques are available to allow the querier to verify the integrity of the result returned by the aggregator node. ::: ::: We propose a novel framework for secure information aggregation in sensor networks. By constructing efficient random sampling mechanisms and interactive proofs, we enable the querier to verify that the answer given by the aggregator is a good approximation of the true value, even when the aggregator and a fraction of the sensor nodes are corrupted. In particular, we present efficient protocols for secure computation of the median and average of the measurements, for the estimation of the network size, for finding the minimum and maximum sensor reading, and for random sampling and leader election. Our protocols require only sublinear communication between the aggregator and the user. <s> BIB007
results from recent studies show that public key cryptography might be feasible in sensor networks BIB004 BIB006 , it remains for the most part infeasible in WSNs. Instead, most security schemes make use of symmetric key cryptography. One thing required in either case is the use of keys for secure communication. Managing key distribution is not unique to WSNs, but again constraints such as small memory capacity make centralized keying techniques impossible. Straight pairwise key sharing between every two nodes in a network does not scale to large networks with tens of thousands of nodes, as the storage requirements are too high. A security scheme in WSNs must provide efficient key distribution while maintaining the ability for communication between all relevant nodes. In addition to key distribution, secure routing protocols must be considered. These protocols are concerned with how a node sends messages to other nodes or a base station. A key challenge is that of authenticated broadcast. Existing authenticated broadcast methods often rely on public key cryptography and include high computational overhead making them infeasible in WSNs. Secure routing protocols proposed for use in WSNs, such as SPINS BIB002 , must consider these factors. Additionally, the constraint on energy in WSNs leads to the desire for data aggregation. This aggregation of sensor data needs to be secure in order to ensure information integrity and confidentiality BIB003 BIB007 . While this is achievable through cryptography, an aggregation scheme must take into account the constraints in WSNs and the unique characteristics of the cryptography and routing schemes. It is also desirable for secure data aggregation protocols to be flexible, allowing lower levels of security for less important data, thus saving energy, and allowing higher levels of security for more sensitive data, thus consuming more energy. As with any network, awareness of compromised nodes and attacks is desirable. Many security schemes provide assurance that data remain intact and communication unaffected as long as fewer than t nodes are compromised BIB005 . The ability of a node or base station to detect when other nodes are compromised enables them to take action, either ignoring the compromised data or reconfiguring the network to eliminate the threat. The remainder of this article discusses the above areas in more detail and considers how they are all required to form a complete WSN security scheme. A few existing surveys on security issues in ad hoc networks can be found in  BIB001  ; however, only small sections of these surveys focus on WSNs. A recent survey article on security issues in mobile ad hoc networks also included an overview of security issues in WSNs  . However, the article did not discuss cryptography and intrusion detection issues. Further, it included only a small portion of the available literature on security in WSNs. The rest of this article is organized as follows. Background information on WSNs is presented, followed by a discussion of attacks in the different network layers of sensor networks. Then we focus on the selection of cryptography in WSNs, key management, secure routing schemes, secure data aggregation, and intrusion detection systems. We discuss future research directions on security in WSNs and then conclude the article.