What is Message Digest

IoT and cloud computing are the novel fields that are rapidly progressing in the world of internet technology. A huge and massive amount of data are communicating via IoT and cloud devices. Along with the highly configured devices, IoT and cloud also empowered many resource-constrained devices to communicate and compute information through network. But the major problem that they face is how to provide data security through conventional cryptographic algorithms in such resource-constrained devices having smaller size, limited memory spaces, low computation capabilities, and limited power. In this scenario, the biggest driver towards the problem is lightweight cryptography (LWC). This chapter discusses thoroughly the LWC, different schemes of LWC, and cryptanalysis of different LWC schemes.