we got handed these at OSFC. The app it comes with: https://github.com/tillitis/tillitis-key1-apps/blob/main/signerapp/main.c

which they use to implement an ssh agent. The device looks like a serial. It's a lattice FPGA and the bitstream (which you can change) is a picorv32.

But could we write a different app, which would implement factotum? Be aware you are memory constrained. 

Anyway, thought this might be of interest.

ron