Homomorphic Multiplicative Encryption Technique using RSA Public key Encryption Algorithm using publish subscribe messaging scheme with MQTT /Coap for Encrypting any sensitive records and deploying it in cloud, i was exploring this use case and did some hands on by implementing the algorithm and deploying a GUI in cloud is one of very good ideas i came across and quote that it could be scaled to any area like predicates matching, category matching of documents based criticality usage of NLP and AI Techniques.
It depends on IoT applications. e.g. 1. Lightweight encryption algorithms can be used for securing the current IoT. 2.NLFBSR is an example to increase the key randomness. 3. All methods used in source and channel coding can be modified to secure IoT. Please check this out.. Good luck.