This paper presents iBatch, a middleware system running on top of an operational Ethereum
network to enable secure batching of smart-contract invocations against an untrusted relay
server off-chain. iBatch does so at a low overhead by validating the server's batched
invocations in smart contracts without additional states. The iBatch mechanism supports a
variety of policies, ranging from conservative to aggressive batching, and can be configured
adaptively to the current workloads. iBatch automatically rewrites smart contracts to integrate …