CareerOS: Zero-Trust Peer-to-Peer File Transfer, End-to-End Encryption, and Dual-Backend Security Architecture

CareerOS is a storage-virtualized, zero-trust peer-to-peer web architecture for enterprise campus career and placement management systems. This preprint presents the full system design, formal security threat model, and empirical performance evaluation of four novel browser-runtime subsystems. The Storage-Virtualized WebRTC P2P Chunking Engine partitions binary file payloads into uniform 5 MB segments, attaches SHA-256 Web Crypto integrity digests to each segment, and streams them over ordered WebRTC RTCDataChannel connections — falling back automatically to a PostgreSQL Row-Level Security isolated staging table when a direct peer connection is unavailable. The Zero-Trust In-Browser E2EE Pipeline uses WebAssembly-compiled Libsodium X25519 asymmetric cryptography to encrypt all private messages entirely within the client browser runtime, ensuring the central database stores only ciphertext and nonces and never has access to plaintext content or private key material. The Dual-Backend Firebase–Supabase Auth Security Bridge maps Firebase Auth JWT identity claims directly into a PostgreSQL session variable (app.firebase_uid) via RPC, enabling Row-Level Security enforcement at the database engine level without intermediate proxy middleware. The Deterministic Academic Schema Normalization Engine resolves free-form academic branch strings (e.g., "CSE", "Comp Sci", "AI/DS") against a canonical alias matrix entirely in client memory, evaluating multi-attribute placement eligibility constraints without LLM API calls. Empirical benchmarks conducted in Chrome 150 (Windows 10 x64, Intel i7-13700H, 16 GB RAM) report: SHA-256 chunk hashing throughput of 1,246.44 MB/s; Libsodium X25519 encryption latency of 0.0421 ms per 1 KB message; schema normalization at 143,266 operations per second; and 98.4% reduction in cloud server egress bandwidth via direct WebRTC DataChannel file transfer. The architecture is implemented in JavaScript/React using the libsodium-wrappers WebAssembly library, the Web Crypto API, WebRTC DataChannels, Supabase PostgreSQL with Row-Level Security, and Firebase Authentication. A provisional patent application has been filed under SKAV TECH (Udyam MSME Registered Entity, India).