# Real-Time, Content-Based Communication Load Reduction in the Internet of Multimedia Things
## 2 Related Research and Background
### Challenges in IoT
#### 2.1.4 IoT Security  
The IoT, though in high demand, also has many security concerns. Different layers of the Open Systems Interconnection (OSI) protocol model are affected by different attacks. Either an insider or outsider can cause attacks [25]. Outsider attacks are easy to detect but insider attacks are not easily detectable because, an adversary contaminates a legitimate node, which may be difficult to detect. An intruder in the network can intercept, modify and inject false data by interrupting the transmission of data, adding a malicious node to the network, which may then forward messages through the network to stay undetected. Maintenance of general security, as well as privacy of information in the IoT, use of lightweight cryptographic algorithms, proper measures for authorization and authentication of network nodes and prevention of malware are the major challenges, which are now attracting the attention of researchers [26]. Many video-based applications particularly used for surveillance, need protection of the information these applications are using. Cameras are installed for monitoring houses, buildings, markets, hospitals, roads, and banks. These sensors are continuously sensing and sending data to monitoring devices. If these devices become vulnerable, an intruder may enter the network as a legitimate node and read all the information being exchanged. That intruder can manipulate the data or even send repeated data in the form of video frames, stalling the video stream at the receiver side. An outsider can manipulate or use sensor-detected information to cause harm. For instance, a patient being remotely monitored will suffer adverse effects on their health if an intruder in the network corrupts the information being sent from a biomedical sensor. Biomedical sensors attached to the body of a patient measure the vital signs of the human body, such as the blood pressure, heart beat, and so on. In the event of an infected network, data can be forged, which may prevent a physician from timely checking upon a patient or giving the patient the wrong treatment. Data is vulnerable to many threats [27], including unauthorized access to a network; data tampering; false data and selective reporting. Similarly, for smart home applications, changes to data by an intruder can cause harm. For example, a fire alarm system, which continuously monitors its surroundings, may be falsely activated by changing detected information. Just intercepting the data bearing the room temperature in a house, can allow an intruder to guess whether the house is occupied or not before breaking in to a house. Solutions to prevent attacks upon the IoT should be applied taking into account the limited resources available to the networked devices. For prevention of jamming, a packet can be divided into chunks to exhaust the energy of a jammer during transmission of that packet. Protocols used in each layer can also be modified if necessary, to make devices immune to intrusions. Lists can be createdfor maintaining records of normal and faulty data to prevent Denial of Service (DoS) attacks. Thus, a cryptographic algorithm with three components namely Feistel Network, Advanced Encryption Standard (AES) S-Box and Genetic Algorithm is given in Reference [27]. The original file is divided into multiple blocks which aid in creating a cipher key that is used by the AES encryption to generate a cipher text and inject it in to the next component [28]. Here, the cipher text undergoes crossover and mutation producing a cipher block. This algorithm is resource-efficient and robust against DoS and tampering attacks. In general, strong cryptographic methods can help secure data over the network. However, due to constrained resources, lightweight cryptosystems must be used, which suit to these devices. An asymmetric cryptography algorithm such as Rivest-Shamir-Adleman (RSA) is not suitable for low-resourced devices due to its complexity.