SecureQR

Cryptographically Signed & Verified QR Code Platform

backend running link: secureqrcicd-2u7vo.ondigitalocean.app

SecureQR is a full-stack cryptographic QR system that generates tamper-proof, verifiable, and optionally encrypted QR codes using a root–leaf trust hierarchy inspired by real-world certificate authorities.

It allows anyone to:

Generate signed QR codes

Verify QR authenticity

Sign / Verify plain text

Encrypt / Decrypt messages

Establish trust using cryptographic chains

Tech Stack

Frontend

React (Vite)

Axios

HTML5 / CSS

Backend

Java 21

Spring Boot 3.3.5

Spring Data JPA

MySQL (DigitalOcean Managed)

Cryptography

ECDSA (for signing)

ECDH + AES-GCM (for encryption)

RSA (optional support)

QR Engine

ZXing (QR generation & reading)

Infrastructure

Docker

GitHub Actions (CI/CD)

DigitalOcean Droplet

Nginx Reverse Proxy

🧠 Problem Statement

Standard QR codes are:

Easy to copy

Easy to modify

Impossible to verify

SecureQR fixes this by embedding cryptographic proof directly inside QR codes.

Every QR generated is:
✔ Signed
✔ Verifiable
✔ Trusted by a Root Issuer
✔ Optionally Encrypted

High-Level Architecture

User (Browser / Scanner App)

    |
    | 
   HTTPS
    ▼
React Frontend
    |
    | 
REST API
    ▼
Spring Boot Backend
    |
    | 
JPA / Hibernate
    ▼
DigitalOcean MySQL

Core Design: Root → Leaf → Payload Trust Chain

Your system works like a mini Certificate Authority:

Root Issuer -> Leaf Key (per user / alias) -> Signed Payload inside QR

QR Code Structure

Each QR stores this cryptographic JSON:

{
"payload": "Your message here",
"signature": "Base64 ECDSA Signature",
"issuerSignature": "Signature from Root on leaf key",
"pub": "Leaf public key Base64", "issuerId": "ROOT-ISSUER-1"
}

Example Use Case – Two Users Secure Messaging

User 1:

Gets public key of User 2

Encrypts message using Encrypt tool

Generates signed QR with encrypted content

User 2:

Scans QR

Verifies authenticity

Decrypts using their private key

Result: ✔ Trusted ✔ Confidential ✔ Unforgeable

Author

Gausul Wara

https://www.linkedin.com/in/gausul-wara-643783256/

Documentation Complete . Thank you so much for your valuable time!