# Efficient Concurrent Execution of Smart Contracts in Blockchains using Object-based Transactional Memory

## TL;DR

This paper introduces an object-based transactional memory framework for efficient concurrent execution of smart contracts in blockchains, utilizing multi-threaded miners and validators to improve performance and security.

## Contribution

It presents a novel framework combining object semantics with multi-version transactional memory for concurrent smart contract execution, including mechanisms to detect malicious miners.

## Key findings

- Significant performance improvements over existing frameworks
- Effective detection of malicious miners using SMV
- Deterministic re-execution of SCTs based on Block Graph

## Abstract

This paper proposes an efficient framework to execute Smart Contract Transactions (SCTs) concurrently based on object semantics, using optimistic Single-Version Object-based Software Transactional Memory Systems (SVOSTMs) and Multi-Version OSTMs (MVOSTMs). In our framework, a multi-threaded miner constructs a Block Graph (BG), capturing the object-conflicts relations between SCTs, and stores it in the block. Later, validators re-execute the same SCTs concurrently and deterministically relying on this BG. A malicious miner can modify the BG to harm the blockchain, e.g., to cause double-spending. To identify malicious miners, we propose Smart Multi-threaded Validator (SMV). Experimental analysis shows that the proposed multi-threaded miner and validator achieve significant performance gains over state-of-the-art SCT execution framework.