  The Internet of Things (IoT) being a promising technology of the future is
expected to connect billions of devices. The increased number of communication
is expected to generate mountains of data and the security of data can be a
threat. The devices in the architecture are essentially smaller in size and low
powered. Conventional encryption algorithms are generally computationally
expensive due to their complexity and requires many rounds to encrypt,
essentially wasting the constrained energy of the gadgets. Less complex
algorithm, however, may compromise the desired integrity. In this paper we
propose a lightweight encryption algorithm named as Secure IoT (SIT). It is a
64-bit block cipher and requires 64-bit key to encrypt the data. The
architecture of the algorithm is a mixture of feistel and a uniform
substitution-permutation network. Simulations result shows the algorithm
provides substantial security in just five encryption rounds. The hardware
implementation of the algorithm is done on a low cost 8-bit micro-controller
and the results of code size, memory utilization and encryption/decryption
execution cycles are compared with benchmark encryption algorithms. The MATLAB
code for relevant simulations is available online at https://goo.gl/Uw7E0W.
