Blockchain Approaches for Secure Financial Transactions in DeFi and Auditing: A Comprehensive Review

Abstract

Blockchain technology is becoming an important tool for secure financial transactions. It supports decentralized finance (DeFi) services and new ways of auditing. This paper gives an overview of how blockchain is used in financial modeling, focusing on DeFi and auditing. We explain the basic technology behind popular blockchain systems, like public platforms such as Ethereum (with smart contracts and oracle networks), and private systems like Hyperledger Fabric. We also look at advanced methods like zero-knowledge proofs. We show how these tools help build financial models in DeFi by allowing peer-to-peer services without needing trust, and in auditing by making data more transparent and secure. We compare different blockchains in terms of speed, cost, and how well they scale. Security issues (like smart contract bugs or attacks on consensus) and practical problems (like trusting oracles and following laws) are also discussed. The review article looks at challenges in using blockchain and some of the latest solutions, such as Ethereum’s move to proof-of-stake, sharding for better scalability, and using zero-knowledge proofs for privacy. We also suggest future research topics, like connecting different blockchains, checking smart contracts with formal methods, creating better rules and laws, and training skilled workers. The goal is to help researchers and professionals understand the current situation and future of blockchain in finance and auditing.