  Blockchain technologies originate from cryptocurrencies. Thus, most
blockchain technologies assume an environment with a fast and stable network.
However, in some blockchain-based systems, e.g., supply chain management (SCM)
systems, some Internet of Things (IOT) nodes can only rely on the low-quality
network sometimes to achieve consensus. Thus, it is critical to understand the
applicability of existing consensus algorithms in such environments. We
performed a systematic mapping study to evaluate and compare existing consensus
mechanisms' capability to provide integrity and security with varying network
properties. Our study identified 25 state-of-the-art consensus algorithms from
published and preprint literature. We categorized and compared the consensus
algorithms qualitatively based on established performance and integrity metrics
and well-known blockchain security issues. Results show that consensus
algorithms rely on the synchronous network for correctness cannot provide the
expected integrity. Such consensus algorithms may also be vulnerable to
distributed-denial-of-service (DDOS) and routing attacks, given limited network
throughput. Conversely, asynchronous consensus algorithms, e.g.,
Honey-BadgerBFT, are deemed more robust against many of these attacks and may
provide high integrity in asynchrony events.
