Existing distributed ledger implementations – specifically, several blockchain implementations – embody a cacophony of
divergent capabilities augmenting innovations of cryptographic hashes, consensus mechanisms, and asymmetric
cryptography in a wide variety of applications. Whether specifically designed for cryptocurrency or otherwise, several
distributed ledgers rely upon modular mechanisms such as consensus or smart contracts. These components, however, can
vary substantially among implementations; differences involving proof-of-work, practical byzantine fault tolerance, and
other consensus approaches exemplify distinct distributed ledger variations. Such divergence results in unique
combinations of modules, performance, latency, and fault tolerance. As implementations continue to develop rapidly due
to the emerging nature of blockchain technologies, this paper encapsulates a snapshot of sensor and internet of things (IoT)
specific implementations of blockchain as of the end of 2016. Several technical risks and divergent approaches preclude
standardization of a blockchain for sensors and IoT in the foreseeable future; such issues will be assessed alongside the
practicality of IoT applications among Hyperledger, Iota, and Ethereum distributed ledger implementations suggested for
IoT. This paper contributes a comparison of existing distributed ledger implementations intended for practical sensor and
IoT utilization. A baseline for characterizing distributed ledger implementations in the context of IoT and sensors is
proposed. Technical approaches and performance are compared considering IoT size, weight, and power limitations.
Consensus and smart contracts, if applied, are also analyzed for the respective implementations’ practicality and security.
Overall, the maturity of distributed ledgers with respect to sensor and IoT applicability will be analyzed for enterprise