Communication that takes place between device and applications or cloud services should be secured. Most times, such communication is not at all encrypted, which makes it easy for hackers to get access to actual data that might be of importance such as medical data, bank-related data, or even something related to a nation's security. So, network security is of utmost importance.
The solution is to make use of Transport Level Security (TLS) / Secured Sockets Layer (SSL) certificates at the device and application/cloud level to encrypt the data before sending it. We can set up private networks as well for isolating devices from public. These cloud service providers give additional security features as part of their services, which can be used to further enhance the security of the IoT system.