Quantum Hash Function - Bhvyadhirr Bharadwaj

Inspiration

In the face of an approaching quantum future, cryptography is undergoing one of the most disruptive paradigm shifts since its inception. From post-quantum algorithms to quantum key distribution, we’re entering uncharted territory. As part of this evolving narrative, I’ve built a prototype quantum hash function named Mark-1—a simulated experiment that explores how quantum mechanics can be harnessed to build the cryptographic primitives of tomorrow.

What it does

Mark-1 is a prototype hash function built atop parameterized quantum circuits, designed to accept classical inputs and output deterministic hash-like signatures derived from quantum state manipulations. It simulates a 16-qubit, 3-layer entangled quantum circuit that: Encodes classical input into rotation parameters, Entangles qubits in alternating block layers, Outputs signatures from the final statevector of the circuit.

The hash is derived from the real/imaginary parts of selected amplitudes in the final quantum state. Note: This is a simulated model, not yet deployable on live quantum hardware. But it’s a step forward in thinking how quantum-native cryptographic functions might work.

How we built it

Project Structure:

quantum_hash_project/ │ ├── analysis/ # Contains all hash analysis scripts │ ├── test_entropy.py # Entropy preservation tests │ ├── test_collisions.py # Collision checks │ ├── test_avalanche.py # Avalanche effect analysis │ ├── test_bit_independence.py # Bit-independence criterion │ ├── quantum_hash/ # Core implementation │ ├── init.py # This should exist (even if empty) │ ├── circuit_builder.py # Builds the parameterized quantum circuit │ ├── input_encoder.py # Compresses and encodes input into parameters │ ├── hash_core.py # Ties everything into a working hash function │ ├── main.py # Input/output runner ├── requirements.txt # Qiskit + numpy + matplotlib └── README.md # Project overview

Challenges we ran into

To test the robustness of the prototype, I ran it through four classical hash evaluation benchmarks: Entropy Test Avg entropy per byte (100 samples): ~1.74 to 2.31 bits Max possible: 4 bits/byte (32-byte hash)

Collision Test 0 collisions across 1000 randomly generated 32-byte inputs

Avalanche Effect Flipping a single bit in the input caused 72 out of 128 bits to flip in the output

Bit Independence Avg deviation from 50% bit distribution: 6.21 bits Max deviation: 23 bits

These results, while still improvable, showcase early evidence of desirable cryptographic properties like diffusion and randomness—even at the simulation level.

Accomplishments that we're proud of

Mark-1 may not be battle-ready for secure blockchain protocols today—but it opens the door to how we might build cryptography for a quantum-first world.

What we learned

To not give in - even in the face of Armageddon.

What's next for Quantum Hash Function - Bhvyadhirr Bharadwaj

Mark-1 is a first prototype in a growing space. Here's what’s next: Move from statevector simulations to measurement-based outputs Add post-processing layers to improve statistical uniformity Run experiments on real IBM quantum hardware Extend to Mark-2, incorporating dynamic circuits and quantum randomness

Built With

• python
• qiskit