Case study / Blockchain
Building a Post-Quantum Blockchain
Qbitcoin combines full-node engineering with Falcon-512 signature integration and P2P networking.
- Product
- Post-quantum blockchain
- Role
- Lead Blockchain Developer & Cryptography Engineer
- Period
- January 2024–February 2026
- Status
- Public repository
- Stack
- Python, Falcon-512, Kademlia DHT, JSON-RPC, gRPC
The problem
A blockchain has to apply the same transaction and block rules across independent nodes. It also needs network discovery, verifiable data structures and usable interfaces for wallets and explorers. Qbitcoin added a specific cryptographic goal: replacing ECDSA signatures with Falcon-512.
Architecture and contribution
I built Python full-node components including a consensus engine, Merkle tree verification, peer discovery and block propagation. A Kademlia DHT supports peer discovery. JSON-RPC and gRPC endpoints expose node operations to wallets, a block explorer and integration clients.
The signing path includes Falcon-512 key generation, signing and signature verification. A post-quantum signature choice affects key and transaction formats as well as validation rules, so integration belongs in the protocol flow rather than in a detached cryptography demo.
Engineering considerations
For node software, deterministic validation and clear error handling matter because peers may send malformed or incompatible data. Signature checks, transaction processing and Merkle verification are all part of the same trust boundary. Public source is available for readers who want to inspect the implementation.
Outcome and evidence
The project includes a full-node implementation and interfaces for ecosystem clients. I have not included unverified adoption, throughput or independent audit claims.
Related services
Blockchain Development · Cryptography Engineering · Privacy & Secure Systems
Have a project in mind?
Let’s talk about a blockchain protocol.
Share your goals, current system and timeline. I can help scope the architecture and implementation.