The pi has a hardware number generator

About the cost, like Aura mentioned, most of the components are probably already lying around (wire, usb cable, sd card,..) or cost almost nothing (like the buttons). You can even make a box from recycled cardboard if you want to save a couple of bucks!

Security is a big topic. In term of trust, to reply to birtart, I think the product is equal to trezor. I use the same code as trezor with a slight modification. Both code, original trezor and mine are open source so open the the eyes of anybody. Both image, mine and original trezor can be easily recreated from scratch (recompiled) just by installing docker and running a script. So if you don't trust my download or trezor firmware you can build it yourself and examine the build process. In term of hardware, both trezor and pi zero are made of standard of-the-shelf components. The pi zero and trezor schematics are both available for examination. And since they both use standard components, they are both sensible to possible back door or bug that could made from manufacturers.

The main difference about security is the security of the flash memory. For the trezor, it is very complicated (not impossible ) to dump the flash and get the privates key and seed. On pitrezor, this is relatively easy because it is on the sdcard. But, if you protect physically your sdcard and use a pass phrase you are in good position because the pass phrase is never stored on the sd card.

Compared to the price of the trezor I think this could represent a good alternative for somebody who do bitcoin transaction occasionally and don't want to pay for a real trezor hardware. You have to take some precaution when you store the device or at least the sd card (in a safe place). This is more user friendly than going back to paper wallet and cold storage. For somebody that perform a lot of transaction and/or carry the device everywhere with him, the real thing is probably better.

Hi Bitcoin fans!

I ported the code of the Bitcoin trezor wallet to Linux to be able to run it on a raspberry pi zero. The raspberry pi zero is a very popular, small and cheap computer that is available for approximately 5$. The choice of the pi zero is interesting because it can be used as a usb device when plugged on a host computer.

This allow anybody to build its own hardware wallet at a very low cost with a good level security if used with a pass phrase.

All the instructions to build it are on my blog here:

https://www.pitrezor.com

On my site I explain how to assemble the buttons like the real trezor and connect an oled display. The oled is optional because I also support the hdmi output of the pi zero directly.

The software image is ready to download and flash on an SD Card. The Linux image is based on Yocto which allowed me to build a very minimal Linux system with only the bare minimum softwares to run my application. All code modifications are public and the software image can easily be rebuild (with docker).

Yannick

please provide me wiki access. My username is yheneaul