SECURE FREELANCER CONTRACT CREATION PLATFORM WITH DIGITAL SIGNING AND PAYMENT TRACKING

Abstract

The rapid growth of freelance and contractbased digital work has increased the need for secure platforms that can manage contracts, payments, and confidential document exchange. Traditional freelance management methods rely heavily on email communication, manual contract handling, and unprotected file sharing, which expose sensitive contractual and financial information to unauthorized access, data leakage, and manipulation. Most existing systems focus on workflow automation but provide limited encryption and insufficient control over document-level security. The traditional system lacks centralized access control, encrypted storage, and reliable audit mechanisms. Contracts and deliverables are often exchanged as plain files without cryptographic protection, making them vulnerable to interception and misuse. Password handling and role validation are frequently weak, and data storage mechanisms do not ensure confidentiality or traceability of user actions. To address these limitations, this research proposes a secure freelance contract management and encrypted file-sharing system developed using Python and the Flask web framework. The system implements role-based authentication for administrators, employers, and freelancers, supported by secure login sessions. Sensitive data such as files, confidential messages, and shared secrets are protected using ShangMi 4 (SM4) symmetric encryption with Secure Hash Algorithm 256 (SHA-256) derived keys before storage or transmission. User credentials are stored in hashed form to prevent direct exposure. The application uses TinyDB, a lightweight NoSQL database, to store users, contracts, payments, encrypted file metadata, messages, secrets, and audit logs in structured JSON format. Encrypted files are stored in protected server directories, and access is strictly controlled based on user roles and ownership. Modular separation between the frontend, backend, encryption utilities, and database layer ensures secure and efficient workflow execution. This research enhances confidentiality, access control, and traceability while maintaining low computational overhead. It is suitable for academic environments and small-scale secure collaboration platforms, demonstrating the effective integration of encryption with webbased contract management systems.