## 6 IoT Security
Message limitations, i.e., limited to about 140 messages per day, minimize the effects of bluff attacks; in the case of healthcare, even a small amount of fraudulent information affects the performance of the healthcare system and can degrade the patient's condition. The performance of Sigfox is suitable for non-critical purposes for which acknowledgements and message delivery receipts are unimportant. However, for healthcare applications, successful message transmission at an appropriate speed is essential. Security compromises may be harmful to patients and affect medical records. Therefore, it is recommended that Sigfox be avoided for critical healthcare applications. The LoRaWAN standard provides security by assigning a unique key to every node in the network that is known only to the network provider and the node. This measure can prevent man-in-middle attacks, with percept encoded and not interpretable [99]. A node with a unique key would fail, and the key would be detected using sophisticated castrate hardware or using a network attack in the server. If a key were identified, then attackers could easily use future messages from the node or transmit malicious messages to the base station. For appropriate security, key management must be taken care of by service providers and developers to protect sensitive data in healthcare databases from malicious attacks. Therefore, LoRaWAN can not sufficiently provide total security. Narrowband IoT follows 3 GPP S3 security levels both in the application and transport layers [100]. It consists of several mechanisms for device identification, entity verification, user identity, data integrity, etc. It also supports optional mechanisms to ensure data confidentiality, application authentication, etc. An optional encryption approach is recommended for real threats that arise in radio communication to protect delicate health-related data. The use of narrowband IoT with all optional and mandatory mechanisms is a secure approach for healthcare applications. It is secure and highly efficient and supports long-range communication between multiple devices. In the application layer scheme, a signal-scrambling key is delivered to authorized parties. The algorithm should be distributed in small data packets to reduce the risk of attacks, as it contains statistically crucial characteristics that reduce the probability of successful transmission and make it easy for an attacker to access the data. The steganography-based technique is used to protect electronic health data using encryption techniques and conceal the data inside the ECG signal, preventing discovery of hidden messages within the health records [101]. The homography encryption method is also used to secure data, allowing for encryption using a public key before it is sent to the cloud. It also follows mathematical functions over the data being encrypted, which enables machine learning without decrypting information in the cloud. If the request is sent by an authorized user, the system using an authority key can use a secure channel with a secret key to encrypt the data. This technique is a promising methods to integrate machine learning and security, but it has not been implemented in IoT-based health care [102]. WBAN applications involve the use of public spaces such as exercise areas and parks. In all cases, users have IOT devices such as smartwatches that collect biosignals from sensors implanted in the human body. The biosignal received from the body is sent to the static sink in the deployed area. Sink nodes contain 5G modules to send the information to the healthcare center for the processing [103]. Sensor nodes face many operational problems because of their low computing capacity, and mobility represents an open challenge in wireless body area networks, which are affected by the loss of messages due to topological calculation. Herein, we discuss a advanced version of MAC named MT-MAC, which was designed to ensure successful delivery of messages.