Unified Fiat and Crypto Payment Platform

Abstract

The evolution of digital payment systems has revolutionized how people transact in modern economies. In India, Unified Payments Interface (UPI) has enabled a massive leap forward in convenience and digital finance adoption. However, cryptocurrency transactions have not kept pace due to infrastructural and usability challenges. Users often navigate multiple platforms, wallets, and address formats, making crypto less accessible. This paper presents UniPay, a unified digital payment solution that integrates fiat (like INR via UPI) and cryptocurrency transactions within a single platform. By bridging this gap, UniPay aims to offer a seamless, secure, and interoperable transaction experience for users and merchants, enhancing financial inclusivity.

Introduction

The text describes the development of UniPay, a unified financial platform designed to bridge the gap between fiat digital payments (like UPI) and cryptocurrencies. While UPI has simplified fiat transactions in India, cryptocurrencies remain underutilized due to complexity, regulatory uncertainty, and cumbersome wallet management. UniPay aims to provide a user-friendly, secure, and compliant interface for seamless real-time fiat-to-crypto and crypto-to-fiat conversions, addressing these barriers.

Key Literature Insights:

• UPI has improved financial inclusion through simplicity and secure authentication.

• Blockchain systems (Bitcoin, Ethereum) enable decentralized, transparent transactions, but mainstream adoption is hindered by technical complexity.

• Hybrid wallet systems combining fiat and crypto have been proposed, but existing solutions often lack full integration or regulatory compliance.

Problem Statement:
Current systems are fragmented, forcing users to manage multiple apps, deal with long crypto addresses, face volatile exchange rates, and navigate unclear regulatory requirements. There is a need for a unified platform that simplifies payments while ensuring security, scalability, and compliance.

Objectives of UniPay:

1. Integrate fiat and crypto payments into a single gateway.

2. Enable instant conversions between INR and cryptocurrencies at live market rates.

3. Support UPI for fiat and Ethereum-compatible wallets for crypto.

4. Replace long wallet addresses with human-readable handles.

5. Ensure KYC/AML compliance and encrypted transaction security.

Methodology & Architecture:
UniPay employs a modular architecture with four core components:

• Unified Wallet Interface: Consolidates fiat and crypto balances, enabling transfers via UPI or blockchain wallets.

• Transaction Routing Engine: Determines the transaction type, executes conversions via liquidity providers or DEXs in real time.

• Blockchain Integration Layer: Uses Ethereum smart contracts for payment verification, identity mapping, and token transfers.

• Banking API Gateway: Interfaces securely with banks and UPI APIs using OAuth2.0 and AES encryption.

Identity is abstracted via a universal transaction ID, allowing human-readable handles and reducing reliance on complex wallet addresses. Real-time AML screening and anomaly detection ensure regulatory compliance.

Implementation Details:

• Platform: Ethereum blockchain, chosen for smart contract support, active ecosystem, and reasonable block times.

• Architecture Components: Smart contracts (Solidity), frontend (ReactJS + Next.js), Web3 integration, MetaMask for wallet management.

• Smart Contract Design: Handles user registration, record creation, verification, and auditability, providing immutable, decentralized transaction records.

• Frontend Features: Role-based dashboards, transaction workflows, verification portals, and record history viewing.

• MetaMask Integration: Facilitates authentication, transaction signing, and network selection without a separate login system.

• Development Stack: Solidity, Truffle, Ganache, ReactJS + Next.js, Web3.js.

Conclusion

This project successfully demonstrates the development of a decentralized, Ethereum-based platform for secure and transparent record management. By harnessing smart contracts, the system eliminates the need for intermediaries, ensures data immutability, and enables real-time verification. The implementation validates key blockchain principles—decentralization, trustlessness, and auditability—in a real-world application setting. The prototype provides a scalable base architecture for integrating more advanced features like UPI payments, decentralized file storage, and mobile access. As blockchain adoption grows and regulatory frameworks mature, systems like ours can play a vital role in transforming trust-based systems into decentralized ecosystems with provable integrity and minimal overhead.

References

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Copyright

Copyright © 2025 Sanjivani Adsul, Tanishka Pimple, Tejas Sarade, Varun Sahu, Kedar Vartak. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.