Sensors and Network Security PDF

**Topic 1 -- Sensors** Temperature sensors measure the ambient temperature by detecting the thermal energy or heat in an environment. The sensor measures the change in the voltage, resistance and current that corresponds to the temperature. Sensors are used within smart homes as a part of climate c...

**Topic 1 -- Sensors** Temperature sensors measure the ambient temperature by detecting the thermal energy or heat in an environment. The sensor measures the change in the voltage, resistance and current that corresponds to the temperature. Sensors are used within smart homes as a part of climate change support systems to ensure energy efficiency while maintaining comfort. They are also used in agriculture to create and maintain optimal growing conditions Humidity sensors measure the amount of moisture in the air by detecting changes in electrical capacitance or resistance caused by the amount of water vapour in the air. They are used in greenhouses to ensure optimal humidity levels for plant growth and for weather monitoring systems for information about water quality and atmospheric conditions Proximity sensors measure the presence or absence of an object within a certain range by detecting changes in electromagnetic fields, light, sound, without physical contact with the object. They are used within automation for example automatic doors and in security systems to trigger an alarm or response when unauthorised access is detected. Motion sensors detect movement or changes in position by measuring changes in infrared radiation (PIR sensors), variations in ultrasonic sound waves or shifts in microwave signals in a defined areas. They are used with security systems too trigger alarms or a surveillance response. They can also tract user activity by using wearable devices for fitness monitoring and health assessments. Light sensors measure ambient light levels by detecting changes in light levels and converting the light into an electrical signal. They often user photodiodes, photocells, or light dependent resistors (LDRs).They are used within lighting control systems, to optimise brightness based on natural light conditions. They are also used to adjust streetlamps lighting in response to daylight. Pressure sensors measure force or pressure exerted on a surface by measuring changes in electrical resistance, capacitance, or piezoelectric output in response to applied pressure which is translated into pressure readings. There are used in automation for tire pressure monitoring to enhance vehicle safety and efficiency. Accelerometers measure acceleration and tilt by detecting changes in velocity along one or more axes and measuring the force exerted when an object moves or changes it orientation relative to gravity. They are used in fitness trackers and other wearable devices to collect movement patterns and translate to health and activity data. Gas sensors detect the presence of specific gasses in the environment. Gas sensors measure the concentration of specific gases in the environment by detecting chemical reactions between gas molecules and the sensing material which creates a change in resistance, capacitance or current. They are used in smoke detectors and carbon monoxide alarms for safety. Sound sensors capture sound waves and convert them to electrical signals by detecting changes in air pressure and converting the vibrations into electrical signals. They are used to monitor noise pollution and for voice recognition by converting spoken words into digital data Image sensors capture visual information and convert it to electrical signals by measuring light intensity to capture the visual information. Used for surveillance cameras and facial recognition. RFID use electromagnetic fields to automatically identify, and track tags attached to objects. The tags contain electronically stored information that can be read from a distance without requiring direct contact or a line-of-sight between the reader and tag. They measure and detect radio waves transmitted between an RFID reader and RFID tag. The tag responds by sending back stored data such as the unique identifier and potentially other information like status or environmental data depending on the tag type. Used in retail to track items and their cost when scanning for purchase and for contactless card payments **Topic 2 -- Network security** **Encryption --** Encryption converts information to ciphertext text to prevent it from being stolen or compromised. **Authentication --** Verifies the identity of a user, process, device to ensure they are who they say they are and only access what they've been permitted to. **Secure Socket Layer (SSL) --** Encrypts and secures data transmitted over the internet, layer 6 of OSI model. It establishes a secure connection between a user's computer and a website or server, or two servers. SLL also provides the user with a digital certificate verifying that the website if safe. SSL prevents hackers from stealing/viewing transferred data such as personal or financial data. **Secure Shell (SSH) --** Encrypts and secures data over the network to secure it and is at layer 7. Main difference between it and SSL is that SSH users a username/password authentication system. **TLS (Transport Layer Security) --** Evolved from SSL, encrypts data sent over the network to secure it and provides end to end security. It operates at layers 4-7. **Wired Equivalent Privacy (WEP) --** encryption traffic using 64 or 128 bit key in hexadecimal. Uses a static key ( a single key) and aimed to prevent man in the middle attacks. **Wi-Fi Protected Access (WPA) --** Replaced WEP. Instead of a static key it used the temporal key integrity protocol (TKIP) to dynamically change the key that systems use. This was introduced to prevent intruded from creating their own encryption key to match the one used by the secure network. **Wi-Fi Protected Access 2 (WPA2) --** Upgrade for WPA. Uses both encryption and authentication and has two modes -- pre shared key (personal), WPA2-PSK, relies on a shared passcode for access and is used in home environments. Enterprise mode, WPA2-EAP more suitable for organisational and business use. Both modes user Counter Mode Cipher Block Chaining Message Authentication Code Protocol (CCMP) to replace TKIP. CCMP is based on the advanced encryption standard (AES) algorithm to provide message authenticity and integrity verification. It is stronger and more reliable thank TKI\[ and makes it harder for hackers to spot patters **Wi-Fi Protected Access 3 (WPA3) --** Upgrade for WPA- 2. Offers individualised data encryption and uses Wi-Fi Device Provisioning Protocol (DPP) and it allows Near Field Communication (NFC) tags or QR codes to allow devices to join a network. It also uses GCMP-256 bit encryption. It also uses Simultaneous Authentication of equals to create a secure handshake, this is where a device connects to a wireless access point and both devices communicate to verify authentication and connection **How to make a network more secure --** Disable SSID broadcasting, enable MAC address filtering, enable a firewall for traffic control, use at least WPA2-PSK (or WPA2-EAP for organisations and businesses) for encryption and authentication, secure passwords, change all default settings.