Implementing System Design: A Use Case Example

This content originally appeared on DEV Community and was authored by IvanDev

Hypothetical Case Study: Innovative Prison Solutions - Implementing Digital Wallets with Blockchain Technology

Disclaimer: This hypothetical case study is designed for educational purposes and is not intended to represent a real-life project because it needs many improvements.

Introduction

Innovative solutions can transform various industries, including the correctional system, in the ever-evolving landscape of technology. This article explores a visionary project to revolutionize prison finances by implementing a blockchain-based digital wallet system for inmates. This system will enhance the prison environment's security, transparency, and efficiency.

Digital money in prisons offers numerous benefits. It reduces the risks associated with handling physical cash, ensures accurate tracking of inmate funds, and facilitates seamless transactions within the prison. Integrating blockchain technology further enhances these benefits by providing a secure, immutable ledger for all transactions.

Requirements Specification

Functional Requirements

Inmate Booking

The system must allow administrators to enter and store detailed information about each inmate when booked into the prison, including personal details, booking date, and available funds.
The system must automatically create a digital wallet for each inmate, initialized with the amount of money they have when booking.

Digital Wallet

Each inmate's digital wallet must securely store their available digital credit.

The wallet should support transactions such as adding credit, deducting credit for purchases, and viewing transaction history.

Purchases within the Prison

Inmates should be able to purchase using their digital credit at authorized prison facilities.

Each purchase transaction is securely uploaded to the database system, with details including the item purchased, the amount deducted, and the date and time of the transaction.

Security

All transactions must be encrypted and securely transmitted to prevent unauthorized access.

The current user must use blockchain technology to ensure the immutability and transparency of all transaction records.

Administrative Functions

Administrators should have access to tools for monitoring and managing inmate accounts, including adding or removing credit, viewing transaction history, and generating reports on inmate spending.

Non-Functional Requirements

Scalability

The system must be able to handle a large number of inmates and transactions without performance degradation.

Performance

It must process the system transaction in real time to ensure accurate and up-to-date account balances.

Security

All inmate data and transaction records must be encrypted and securely stored to prevent unauthorized access.
Blockchain technology must ensure the immutability and transparency of all transaction records.

Usability

The system must have an intuitive and user-friendly interface for inmates and administrators, with easy-to-navigate menus and clear task instructions.

Use Case Diagram

The use case diagram visualizes user interactions (inmates, admins) and the system, highlighting key functionalities such as inmate booking, digital wallet management, purchases, and administrative tasks.

Design

High-Level Design

System Architecture

The overall system architecture includes the following components:

• Inmate Management System: Handles inmate details, booking information, and digital wallet creation.

• Digital Wallet: Manages inmate funds, supports transactions, and maintains balance records.

• Transaction Processing System: Processes purchases made by inmates and updates digital wallet balances.

• Blockchain Integration: Ensures secure, immutable records of all transactions.

• Administrative Interface: Provides tools for administrators to monitor and manage inmate accounts.

Component Diagram

The component diagram illustrates how different parts of the system interact, including the inmate management system, digital wallet, transaction processing, blockchain integration, and administrative interface.

Detailed Design

UML Diagrams

Use Case Diagram

The Use Case Diagram visualizes user interactions (Inmates and Admins) and the system, highlighting key functionalities such as inmate booking, wallet management, purchases, and administrative tasks.

Explanation: The Use Case Diagram outlines the interactions between actors (Inmates and Admins) and the system, highlighting the main functionalities provided by the system.

• Inmate: Can make purchases and view transaction history.
• Admin: Can book inmates, manage accounts, and generate reports.

The diagram shows the system's major use cases or functionalities and the interactions between users and system components, providing a high-level overview of user interactions.

Class Diagram

The class diagram shows the classes involved in the system, such as Inmate, Wallet, Transaction, and Admin.

Explanation: The Class Diagram represents the system's static structure. It shows the main classes involved, their attributes (data), methods (functions), and the relationships between them.

• Inmate: Contains information about each inmate and is associated with a Wallet.
• Wallet: Manages digital credit, supports transactions, and maintains a transaction history.
• Transaction: Represents individual financial transactions, including the amount and type.
• Admin: Manages inmate accounts, including adding or removing credit, viewing transaction histories, and generating reports.
• Report: Represents the generated reports for administrative purposes.

The diagram helps us understand how different system components interact and are organized.

Sequence Diagram

The sequence diagram illustrates the sequence of interactions for critical processes, such as booking an inmate and making a purchase.

Explanation: The Sequence Diagram illustrates the sequence of interactions between various actors (Admin, Inmate) and system components (System, Wallet, Blockchain, Database) during critical processes.

• Inmate Booking: This shows how an Admin books an inmate, creates a digital wallet, and stores details.
• Making a Purchase: This demonstration demonstrates the process of an inmate making a purchase, with credit deducted from their wallet and the transaction recorded.
• Managing Accounts: Details how Admins manage inmate accounts by adding or removing credit and updating details.
• Generating Reports: Describes how to create reports by retrieving data from the database.

The diagram provides a dynamic view of how different system parts work together over time.

Activity Diagram

The activity diagram shows the workflow of processes like inmate booking and transaction processing.

Explanation: The Activity Diagram depicts the workflow of various processes within the system. It illustrates the activities involved in critical processes like booking an inmate, purchasing, and managing accounts.

• Inmate Booking: Includes steps for entering details, creating a wallet, and storing information.
• Making a Purchase: Shows the purchasing process, including authentication and wallet updates.
• Managing Accounts: Details how Admins add or remove credit and update account details.
• Generating Reports: Includes steps to retrieve data and create reports.

The diagram helps visualize the flow of activities and decision points in the system's processes, clarifying how different tasks are carried out.

Summary

This article explored a hypothetical case study on implementing a blockchain-based digital wallet system for prison inmates. This system aims to modernize and secure the management of inmate finances, ensuring accurate and transparent transactions within the prison environment. We outlined the functional and non-functional requirements, including the need for real-time transaction processing, high security, and a user-friendly interface. Additionally, we provided various UML diagrams, such as use case, class, sequence, and activity diagrams, to illustrate the design and workflow of the system.

Conclusion

This article presented a use-case example of implementing a blockchain-based digital wallet system within a prison environment, demonstrating how system design principles can address complex real-world challenges. We illustrated the key components and workflows necessary for secure and efficient inmate financial management by outlining the functional and non-functional requirements and providing detailed UML diagrams.

Integrating blockchain technology showcases the potential for enhancing transparency and security in traditional systems. This case study underscores the value of careful system design and planning in developing scalable solutions, offering insights into how modern technologies can be leveraged to improve operational efficiency and integrity.

About the Author

Ivan Duarte is a backend developer with experience working freelance. He is passionate about web development and artificial intelligence and enjoys sharing their knowledge through tutorials and articles. You can follow on X for more insights and updates.

This content originally appeared on DEV Community and was authored by IvanDev