NanoHash Invoice

Invoicing shouldn't be complicated. A simple, lightweight, and fast system with essential features, cryptographic security, and an intuitive user experience.

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Inspiration

Facturing and billing are everyday tasks, yet many existing solutions introduce unnecessary complexity.
NanoHash Invoice was inspired by the idea that a modern invoice system should be simple, lightweight, fast, and intuitive, while still being complete and secure.
We wanted a beginner-friendly project showing how clean design and basic cryptography can improve trust and usability in real-world applications.

What we learned

  • Client-side state management and real-time calculations
  • Browser-based cryptography (SHA-256 hashing)
  • Handling dynamic settings like currency switching (dollar, euro, boliviano) and adjustable Tax Rate (%)
  • How thoughtful UI/UX design balances simplicity, performance, and security

How we built it

  • Technologies: HTML, CSS, and vanilla JavaScript
  • Cryptography: Web Crypto API generates a SHA-256 hash for each invoice
    $$ \text{Hash} = \text{SHA-256}(\text{Invoice Data}) $$
  • PDF export: jsPDF generates professional invoices
  • QR codes: Link invoice identifiers with verification hashes
  • Data storage: LocalStorage keeps invoice history, currency selection, and configuration without a backend

Invoices are calculated automatically:

$$ \text{Subtotal} = \sum_{i=1}^{n} (\text{quantity}_i \times \text{price}_i) $$

$$ \text{Total} = \text{Subtotal} + (\text{Subtotal} \times \text{Tax Rate}) $$

Challenges we faced

  • Integrating cryptographic hashing while keeping it simple for beginners
  • Synchronizing calculations, currency conversion, UI updates, and PDF generation in real time
  • Designing a clean PDF layout that matched the on-screen invoice
  • Allowing users to dynamically change currency and Tax Rate without breaking calculations

Accomplishments

  • Built a complete invoice system that is fast, simple, and intuitive
  • Integrated real cryptographic verification without external services
  • Allowed dynamic currency switching and adjustable Tax Rate
  • Delivered professional PDF invoices entirely on the client side
  • Maintained high performance and clear UX under hackathon constraints

What's next

Future improvements: dynamic exchange rates via APIs, optional backend synchronization, user authentication, and advanced invoice analytics.
Long-term vision: evolve NanoHash Invoice into a scalable, secure, globally usable invoicing solution.

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