Boomerang: Redundancy Improves Latency and Throughput in Payment-Channel Networks

In multi-path routing schemes for payment-channel networks, Alice transfers funds to Bob by splitting them into partial payments and routing them along multiple paths. Undisclosed channel balances and mismatched transaction fees cause delays and failures on some payment paths. For atomic transfer schemes, these straggling paths stall the whole transfer. We show that the latency of transfers reduces when redundant payment paths are added. This frees up liquidity in payment channels and hence increases the throughput of the network. We devise Boomerang, a generic technique to be used on top of multi-path routing schemes to construct redundant payment paths free of counterparty risk. In our experiments, applying Boomerang to a baseline routing scheme leads to 40% latency reduction and 2x throughput increase. We build on ideas from publicly verifiable secret sharing, such that Alice learns a secret of Bob iff Bob overdraws funds from the redundant paths. Funds are forwarded using Boomerang contracts, which allow Alice to revert the transfer iff she has learned Bob's secret. We implement the Boomerang contract in Bitcoin Script

Performance-Based Analysis of Blockchain Scalability Metric

Cryptocurrencies like Bitcoin and Ethereum, are widely known applications of blockchain technology, have drawn much attention and are largely recognized in recent years. Initially Bitcoin and Ethereum processed 7 and 15 Transactions Per Second (TPS) respectively, whereas VISA and Paypal process 1700 and 193 TPS respectively. The biggest challenge to blockchain adoption is scalability, defined as the capacity to change the block size to handle the growing amount of load. This paper attempts to present the existing scalability solutions which are broadly classified into three layers: Layer 0 solutions focus on optimization of propagation protocol for transactions and blocks, Layer 1 solutions are based on the consensus algorithms and data structure, and Layer 2 solutions aims to decrease the load of the primary chain by implementing solutions outside the chain. We present a classification and comparison of existing blockchain scalability solutions based on performance along with their pros and cons

Dependability Auditing with Model Checking

Model checking offers a methodology for determining whether a model satisfies a list of correctness requirements. We propose a theory of dependability auditing with model checking based on four principles: (1) The modeling process should be partitioned into computational components and behavioral components as an aid to system understanding; (2) The complex system will be abstracted to create a model; (3) A language must be available that can represent and evaluate states and processes that evolve over time; (4) Given an adequate model and temporal specifications, a model checker can verify whether or not the input model is a model of that specification: the specification will not fail in the model. We demonstrate this theoretical framework with Web Services and electronic contracting