  Blockchain (BC), a by-product of Bitcoin cryptocurrency, has gained immense
and wide scale popularity for its applicability in various diverse domains -
especially in multifaceted non-monetary systems. By adopting cryptographic
techniques such as hashing and asymmetric encryption - along with distributed
consensus approach, a Blockchain based distributed ledger not only becomes
highly secure but also immutable and thus eliminates the need for any
third-party intermediators. On the contrary, innumerable IoT (Internet of
Things) devices are increasingly being added to the network. This phenomenon
poses higher risk in terms of security and privacy. It is thus extremely
important to address the security aspects of the growing IoT ecosystem. This
paper explores the applicability of BC for ensuring enhanced security and
privacy in the IoT ecosystem. Recent research articles and projects or
applications were surveyed to assess the implementation of BC for IoT Security
and identify associated challenges and propose solutions for BC enabled
enhanced security for the IoT ecosystem.
