We found all the parts needed to build a simple U2F security token thanks to Github. Here’s the link: https://github.com/conorpp/u2f-zero/wiki/Parts-List Basically there are 8 components per token. All should be surface mount parts. Here’s what you need: PART MANUFACTURER PART NUMBER PRICE PER  WHERE TO FIND Microcontroller EFM8UB11F16G-C-QSOP24 $1.38 https://www.digikey.com/ Secure Element (Authentication chip) ATECC508A-SSHDA-B $0.75 …