  Blockchain technology is an interlinked systematic chain of blocks that
contains transaction history and other user data. It works under the principle
of decentralized distributed digital ledger. This technology enables
cryptographically secure and anonymous financial transactions among the user
nodes of the network enabling the transactions to be validated and approved by
all the users in a transparent environment. It is a revolutionary technology
that earned its emerging popularity through the usage of digital
cryptocurrencies. Even though Blockchain holds a promising scope of development
in the online transaction system, it is prone to several security and
vulnerability issues. In this paper, blockchain methodology, its applications,
and security issues are discussed which might shed some light on blockchain
enthusiasts and researchers.
