The security requirements are increasing due to the open nature of the wireless medium. The attackers can monitor or alter the sensitive information that is transmitted across wireless networks. It is necessary to ensure that the message is sent to the destination without alteration. A Dynamic Security management mechanism is proposed  which reduce the risk related to security and process rejection ratio of aperiodic real-time tasks running on servers. The performance of security algorithms are measured with respect to time and energy. The major security issues in wireless networks include confidentiality, availability, integrity, authentication and access control.
A. Data confidentiality
It is the process of ensuring that the information should not be leaked to the attackers. The performance of the security algorithms on constrained devices are accessed which generally arise in IoT networks . The analysis of symmetric and asymmetric algorithms shows that the implementation of symmetric ciphers and hash functions into the IoT is easy task. On the other hand, asymmetric algorithms take more time for execution which causes a delay in processing of IoT applications.
B. Data integrity
It ensures that the information should not be modified during the transmission. A methodology proposed for code integrity monitoring for application-specific processors . The execution trace is monitored online and tests whether it fix with the program behavior that is expected. This proposed system can be used to detect the program code integrity over a wide range. The data should be accessible only to authorized users.
It ensures the identification and confirmation of users in wireless networks. Each user must have username and password in order to access the resources. It enables the enterprises to keep their networks secure by allowing only authenticated parties to access the resources include databases, networks, files, systems, and other network-based services. An end-to-end authenticated double encrypted messaging architecture is proposed . It is based on hybrid RSA algorithm which is specifically applied for future internet architectures. It can work without external digital certificates, provides strong confidentiality and no need of third party authentication. It is an essential security mechanism to ensure data security and privacy.
It is the process of assuring the resources and networks are available for authorized access. The attack prevents the end system to be accessed by the authorized parties.
E. Access Control
It ensures that only the authorized parties should access the resources and the information communicated across the networks. The main challenges in employing access control mechanisms to IoT are addressed . The widely used internet protocols cannot be suitable for constrained environments. A modern access control technique is required for network sharing of IoT.
F. Data freshness
It is the process of confirming that the received process information is latest and previous information has not been replayed. A counter should be included along with the process information to ensure data freshness.
A WSN requires all wireless nodes to be independent and it should have the capability of self-organizing. In sensor network, the infrastructure keeps on changing which are used for the managing the network, which make WSN security more challenging.
H. Time synchronization
The sensor network used in applications is based on some form of time synchronization. It is essential for basic communication and it detects movement, location and proximity. The issues in synchronization include access time, transmit time, receive time and propagation time. It is the problem of synchronizing the clocks across a set of sensor nodes.
I. Secure Localization
The usage of sensor network mostly relies on its ability that it automatically and accurately detects each sensor in the network. In order to point out the accurate fault, the location information is required in a sensor network. An attacker can easily exploit this situation and can manipulate non-secured location information.