Integrated Account System: Objectives and Background – Objectives: Achieve integrated digital identity by unifying distributed Web2/Web3 accounts (e.g., SNS accounts, wallets, etc.) to generate a unique user-specific ID; provide high-security access through mandatory multi-signature authentication ensuring that only the individual can access the account; integrate financial transactions by combining fiat currency operations via Stripe with smart contract-based cryptocurrency management to enable seamless wallet functionality and payment transfers; Background: Users manage multiple Web services and blockchain wallets that are fragmented, creating security and convenience challenges; with the evolution from Web2 to Web3, there is a growing need for reliable integrated accounts offering single sign-on (SSO) and a robust financial transaction platform; a private chain is employed to enhance immutability and auditability, allowing users to set their own access authentication rules (multi-sig) for balanced security and transparency. System Overview – Key Components: User Interface (Web and mobile apps) for integrated account registration, authentication, profile management, wallet balance and transaction display, payment operations, and management of linked SNS/wallet authentications; Authentication Management System that consolidates Web2 (OAuth2/OpenID Connect) and Web3 (wallet integration) authentication, verifying and storing linked data; Identity Aggregation Service that collects authentication data and generates a unique integrated account ID using digital signatures and elements of self-sovereign identity (SSI); Private Chain Module that records integrated account creation details, authentication data, access logs, and transaction histories to ensure immutability, auditability, and tamper detection; Multi-Sig Authentication Protocol requiring all pre-set authentication factors (e.g., three-factor authentication) to succeed before granting account access; Payment/Wallet Module (Stripe integration) for processing fiat transactions via Stripe API/Connect and managing cryptocurrency through smart contract integration; API Gateway that facilitates secure data exchange between internal systems (authentication, aggregation, private chain, payment) and external services (authentication providers, Stripe, etc.). Functional Requirements – (3.1) Account Integration and Authentication: integrate multiple authentication methods (Web2: Google, Facebook, Twitter via OAuth2/OpenID Connect; Web3: Ethereum wallets such as MetaMask, WalletConnect), generate a unique integrated account ID by aggregating authentication data and digitally signing it on the private chain, and enforce multi-sig access control so that only when all required authentication factors succeed does access occur; (3.2) Private Chain Management: record integrated account creation details—including authentication data, digital signatures, and initial security settings—on the private chain, and log access events such as logins, authentication actions, account updates, and payment transactions on-chain to enable tamper detection and auditing; (3.3) Wallet and Payment Functionality: provide an integrated wallet linked to the account for managing balances of both fiat and cryptocurrencies, and enable payment and transfer operations via Stripe for fiat transactions (instant payments, transfers, deposits, withdrawals) as well as smart contract–based automated processing for cryptocurrency transactions and token economy management; (3.4) Single Sign-On (SSO) and Unified Profile: allow seamless login to partnered services through the integrated account and aggregate user data from various authentications into a single, editable profile. Non-Functional Requirements – Ensure robust security through MFA, multi-factor authentication, encrypted communications (SSL/TLS), and AES encryption for data at rest; guarantee immutability via digital signatures and audit logs recorded on the private chain; design for scalability with a distributed architecture capable of handling global user and transaction volumes using blockchain frameworks (e.g., Hyperledger Fabric, Quorum); deliver high performance with real-time processing of authentication, account creation, and wallet/payment operations; offer an intuitive UI/UX for smooth multi-factor authentication and wallet management; and maintain interoperability with Web2/Web3 authentication services, Stripe, and smart contract platforms. System Architecture – High-Level Structure: Client Layer comprising web and mobile applications for account management, wallet operations, authentication integration, and SSO; Authentication Management Server responsible for interfacing with authentication providers and managing token issuance and verification; Identity Aggregation Service that aggregates authentication data, generates integrated account IDs with digital signatures, and records them on the private chain; Private Chain Module that logs integrated account data, authentication records, and access/transaction histories to ensure tamper-proof auditability; Payment/Wallet Server handling fiat transactions via Stripe API/Connect and cryptocurrency processing via smart contracts; and an API Gateway that secures data exchange between internal and external services. Data Design – Key Data Structures: Integrated Account Record containing a unique account ID, basic user information (name, email, profile image, etc.), linked authentication data (Web2/Web3 account IDs, authentication tokens, public keys, etc.), security settings (MFA data, multi-sig rules, digital signature history), and a private chain record hash; Authentication/Operation Logs documenting login timestamps, authentication methods, IP addresses, success/failure statuses, account linking events, profile updates, and access operations; and Wallet/Transaction Data tracking balances for fiat and cryptocurrencies, transaction records (timestamps, statuses, blockchain transaction hashes). API Endpoint Design – Endpoints include POST /linkAccount to link Web2/Web3 authentication data to the account; GET /integratedAccount to retrieve integrated account and linked authentication details; POST /login to process MFA and multi-sig authentication for account access; GET /activityLog to obtain audit logs of authentication, account linking, and wallet/payment operations; GET /wallet to fetch wallet balances and transaction histories; and POST /transfer to handle payment transactions via Stripe and smart contract integration. User Experience (UX) Flow – Account Integration Dashboard displaying linked Web2/Web3 accounts with options to add or remove connections, an integrated profile view aggregating all authentication data for editing, and security settings for MFA, multi-sig configurations, and login history review; Wallet/Payment Interface featuring a dashboard showing fiat and crypto balances with real-time updates and an intuitive UI for executing transfers and deposits via Stripe and smart contracts; and SSO functionality enabling seamless login to partnered services using the integrated account. Security and Compliance – All communications are encrypted using SSL/TLS and data at rest is secured with AES encryption; MFA and multi-sig authentication are mandatory for logins and critical operations; the private chain is used to record account creation, access, and transaction events to ensure tamper-proof audit trails; and the system complies with PCI DSS, GDPR, CCPA, and aligns with Stripe’s security standards. Development Roadmap – Phase 1: Develop a prototype implementing Web2/Web3 authentication integration, integrated account generation, initial private chain linkage, UI/UX design, and API gateway setup; Phase 2: Enhance security with MFA, multi-sig, encryption, and audit log implementation, and conduct end-to-end integration testing from account generation to wallet operations; Phase 3: Add payment and wallet functionality via Stripe API/Connect and smart contract-based cryptocurrency wallet features; Phase 4: Fully deploy the private chain for recording authentication, access, and transaction events, and expand SSO integration with partnered services; Phase 5: Conduct beta testing, security audits, legal validation, and proceed to official release and operation. Testing and Quality Assurance – Include unit tests for individual modules (authentication integration, aggregation, private chain, wallet, payment processing), integration tests covering end-to-end scenarios, security audits by external experts (penetration testing, smart contract audits, private chain verification), and User Acceptance Testing (UAT) based on real user scenarios with feedback integration. Maintenance and Operations – Regularly deploy updates including security patches, feature enhancements, and bug fixes; monitor authentication, access, and wallet/payment transactions in real time with log analysis; provide user support through helpdesks, FAQs, and online assistance; and conduct periodic security audits and compliance updates in response to regulatory changes. Future Expansion and Scalability – Fully implement self-sovereign identity (SSI) for decentralized, user-controlled digital ID management; incorporate AI-based fraud detection analyzing login patterns and payment transactions for early risk identification; diversify payment services by integrating additional providers and blockchain-based payment systems; expand external integrations with SNS, financial, and IoT services for enhanced authentication and SSO; and integrate DGU as a valuation benchmark within the financial transaction system to offer an international, stable value measure through real-time AGI-based DGU calculations and updates, thereby supporting an adaptable and transparent evaluation system for future financial ecosystems. Conclusion – This Integrated Account System unifies diverse Web2/Web3 accounts to deliver a unique, user-exclusive digital ID secured by multi-sig access control and private chain record management; by integrating Stripe-driven payment and smart contract-based wallet functionality, it facilitates seamless management and transfer of both fiat and cryptocurrencies, establishing a comprehensive authentication and financial platform for the transition from Web2 to Web3.