PatinaKey · Hardware

Hardware sources for PatinaKey, an open-source USB security key. Designed in Altium Designer, manufactured at JLCPCB.

Overview

A USB-A key-shaped board carrying two chips: a secure microcontroller (STM32U545) that runs the show, and an open secure element (TROPIC01) that keeps the secrets safe. See the project site for the design rationale.

Specifications

MCU	STM32U545CEU6Q - Cortex-M33 @ 160 MHz, full-speed USB, SMPS (UFQFPN-48)
Secure element	TROPIC01 - Tropic Square (QFN-32)
Interface	USB-A, gold fingers, ENIG finish + 30° bevel
Interaction	Capacitive touch pad (touch-to-confirm) + status LED
Programming	USB-DFU (ROM bootloader) + SWD pogo pads (1.27 mm × 6)
PCB	4 layers, 49.3 × 18.6 mm, FR-4, ENIG

Repository layout

hardware/
├── altium/        # Altium project (.PrjPcb, .SchDoc, .PcbDoc)
├── gerber/        # manufacturing outputs (Gerber + drill)
├── bom/           # bill of materials
├── docs/          # renders, captures, schematic PDF, PickPlace file, PCB PDF
├── MANUFACTURING.md
└── README.md

Reproducing the board

Bare PCB: send the ZIP from gerber/ to a fab house. See MANUFACTURING.md for the exact JLCPCB settings (4-layer, ENIG, gold fingers, plugged vias, stackup).

Assembly: the BOM in bom/ references LCSC parts. ⚠️ The TROPIC01 is not in the JLCPCB library. It is hand-soldered (hot air recommended for the QFN with thermal pad).

Status

Step	State
Schematic	✅
4-layer routing	✅
DRC	✅ clean
Manufacturing files	✅
Prototypes	🔶 on order

License

• Hardware design files are licensed under CERN-OHL-S v2 (see LICENSE).
• Documentation, images and text are licensed under CC-BY-4.0 (see LICENSE-docs).

Disclaimer

Experimental project for learning and research. Not audited, not certified - do not use it to protect real assets as-is. See SECURITY.md.