Reference FPGA Implementation (Cyclone V)

This directory contains the reference RTL modules, precompiled FPGA images, and optional TCL test scripts for the atomic measurement–collapse primitive. This primitive is a CMOS-compatible hardware measurement–collapse mechanism that enforces single-read semantics: the first qualified read returns the stored byte, and the act of measurement deterministically triggers an irreversible collapse event. After collapse, the cell produces only obfuscated or PRNG-derived outputs, ensuring that the original value cannot be recovered. The implementation demonstrates deterministic first-read disclosure, basis-conditioned access control, and atomic one-way state transitions across a bank of independent memory cells.

The provided .sof files allow direct hardware validation without any additional bus interface modules.

Status: Research Artifact Release
License: Non-commercial use only (see LICENSE below)
Patent Pending: US 19/286,600
Target Hardware: Intel Cyclone V (5CSEBA6 / DE-SoC)

📦 Directory Contents

🧩 RTL Overview

collapse_cell.sv

Implements the measurement–collapse read-once memory (ROOM) primitive:

• INIT loads value and basis
• First correct-basis read discloses the stored value and collapses the cell atomically
• All subsequent reads return post-collapse obfuscated bytes

Key internal state:

• basis_valid_q
• armed_q
• collapsed_q

collapse_bank.sv

Implements the full 1024-cell array. This module provides:

• Parallel instantiation of 1024 collapse_cell units
• Address decode and routing for selecting a single active cell
• Uniform broadcast of metadata inputs (basis byte, read pulse, init pulse)
• Aggregation of output paths (data_o, collapsed_q, status, etc.)
• Optional ring-oscillator (RO) drive to support post-collapse oscillation-based entropy/obfuscation at the bank level

The RO path is only active after collapse and contributes to the post-collapse obfuscated output stream when enabled. It does not affect first-read correctness or collapse semantics.

🔧 FPGA Images Provided

Atomic1024Bank.sof

• Clean build without instrumentation
• Used for simple demonstrations and black-box verification

SignalTap.sof

• Same RTL with SignalTap probes enabled
• Captures internal collapse timing at 50 MHz

Probed signals (see SignalTap.stp):

• read_pulse
• basis_in[7:0]
• basis_valid_q
• armed_q
• collapsed_q
• data_o[7:0]
• valid_out (if present)

🗂️ TCL Test Scripts (tcl/)

These optional scripts are provided for users who wish to automate interactions, drive sequences, or reproduce the internal test flow.

Example capabilities include:

• Automated read sequences
• Basis sweep testing
• Collapse confirmation cycles
• Bulk sampling into local logs

These scripts do not depend on any bus interface HDL included in this artifact. Users may adapt them for their own host interface, GPIO sequencer, or System Console workflows.

🖥️ Hardware Usage

1. Open Quartus Programmer
2. Load either Atomic1024Bank.sof or SignalTap.sof
3. Program the DE-SoC using USB-Blaster
4. (Optional) Open SignalTap to observe:
   • First-read disclosure
   • Collapse event
   • Post-collapse output evolution

No Avalon-MM slave or external IP wrapper is required to use these images.

📄 License

See the full LICENSE.md file.
A non-commercial research license applies.

📜 License (Summary)

• Non-commercial research, teaching, and evaluation permitted
• Commercial use requires a separate license from QSymbolic LLC
• Patent rights granted for non-commercial use only
• Attribution required
• No warranty; no liability

This summary is informational only. The full text in LICENSE.md controls.

📚 Citation

If you use this artifact in academic work, please cite the associated paper:

Cite as:
Francis X. Cunnane III. A CMOS Measurement–Collapse Primitive for Ephemeral Secrets in Post-Quantum Cryptography. TechRxiv. December 02, 2025.
https://doi.org/10.36227/techrxiv.176463742.23048082/v3

BibTeX example:

@misc{cunnane2025measurementcollapse,
  author       = {Cunnane III, Francis X.},
  title        = {A CMOS Measurement--Collapse Primitive for Ephemeral Secrets in Post-Quantum Cryptography},
  year         = {2025},
  month        = dec,
  note         = {TechRxiv},
  doi          = {10.36227/techrxiv.176463742.23048082/v1},
  url          = {https://doi.org/10.36227/techrxiv.176463742.23048082/v1}
}