Digital Membership Card System Using STM32 and NFC Architecture Suggestions

[rixcyclint]

Hi everyone, I'm exploring the development of a digital card solution that combines mobile wallets with STM32-based access devices. The idea is to allow members to store a digital membership card on their smartphone while STM32-powered hardware verifies membership at entry points, kiosks, or self-service stations.

Some features under consideration:

1. NFC-based member identification
2. QR code fallback for mobile devices
3. STM32-controlled access terminals
4. Real-time membership validation through cloud APIs
5. Offline verification capability
6. Secure credential storage on embedded devices
7. Event attendance and usage tracking

I'm interested in learning from anyone who has worked on similar embedded access-control or membership systems.

A few questions:

1. Which STM32 series would you recommend for NFC-enabled membership verification devices?
2. What security practices are commonly used for protecting member credentials on embedded hardware?
3. Has anyone implemented offline authentication with periodic cloud synchronization?
4. Are there recommended STM32 libraries or middleware components for this type of application?

Any architecture suggestions, lessons learned, or reference designs would be greatly appreciated.

[Pavel A.]

> I'm interested in learning from anyone who has worked on similar embedded access-control or membership systems.

A good example of such solution is offered by Tigapo. They make STM32-based terminal devices with NFC reader of plastic cards/tokens, cloud  communication for validation and usage tracking, and smartphone app (but IIRC no secure storage of credentials on the device). The terminal has a GUI, of course. Their parent company Nayax makes all kinds of payment terminals worldwide.