D-CERT
A digital diploma platform combining blockchain verification with an AI-powered knowledge retrieval system.
D-CERT addresses the challenges of academic credential fraud and complex institutional document lookup by uniting immutable blockchain verification with an advanced retrieval-augmented generation (RAG) assistant.
The Problem
Verifying academic degrees is traditionally slow and vulnerable to tampering. Simultaneously, navigating institutional regulations, graduation guidelines, and academic records involves labor-intensive manual searching.
The Solution
Constructed a dual-engine platform: smart contracts on Ethereum Sepolia store document hashes for instant, tamper-proof diploma verification; while a Python FastAPI + FAISS vector engine indexes institutional PDFs and queries a local Qwen 2.5 14B LLM for accurate context-grounded answers.
Hybrid microservices architecture: React client interfaces with a Node.js/Express application core for business workflows, an Alchemy-connected smart contract for on-chain verification, and a FastAPI RAG microservice for semantic vector search.
Tamper-Proof Verification
On-chain verification verifying SHA-256 certificate hashes directly against Ethereum smart contracts.
Semantic RAG Search
Specialized Vietnamese embedding model (BKAI Bi-Encoder) coupled with FAISS for semantic document chunk lookup.
Context-Grounded LLM Responses
Qwen 2.5 14B provides hallucination-resistant answers with precise citations to source document pages.
Administrative Portal
Role-based certificate issuance, student record management, and batch document processing.
CHALLENGE:Accurate Vietnamese Semantic Retrieval
Approach: Benchmarked and integrated the BKAI Vietnamese Bi-Encoder to generate high-quality dense vector representations for Vietnamese academic terminology.
CHALLENGE:Gas Optimization & Hash Integrity
Approach: Stored document SHA-256 hashes as compact bytes32 types in Solidity rather than raw string data, reducing on-chain gas costs significantly.
FastAPI service running with local Ollama inference; Node.js core backend; smart contracts deployed to Ethereum Sepolia via Alchemy RPC.
Demonstrated instantaneous diploma authenticity verification and highly accurate Vietnamese academic document querying with zero hallucination.
Technologies Used
Personal Contribution
- ↳Architected the full system integration between Web2, AI service, and Web3
- ↳Developed the FastAPI AI microservice with FAISS and Ollama LLM integration
- ↳Authored and deployed the Solidity certificate registry contract to Sepolia testnet
- ↳Implemented the web frontend and credential lookup portal