  Blockchains are tamper evident and tamper resistant digital ledgers
implemented in a distributed fashion (i.e., without a central repository) and
usually without a central authority (i.e., a bank, company, or government). At
their basic level, they enable a community of users to record transactions in a
shared ledger within that community, such that under normal operation of the
blockchain network no transaction can be changed once published. This document
provides a high-level technical overview of blockchain technology. The purpose
is to help readers understand how blockchain technology works.
