Your cute little new device provides a very secure way to print paper wallets. However, the security of a system is— at best— only as good as its weakest link. So please observe the following words of caution before you begin:
Insert Mycelium Entropy into your printer’s front USB port, the one typically used to print photos from thumb drives and USB cameras.
When the paper wallet image is detected, select the image and hit print.
After printing is complete, it is recommended to cycle your printer’s power before reconnecting it to clear any image cache that may be left in the printer’s memory.
If you wish to create a new paper wallet, push the button on your Entropy device, and wait a few seconds for your printer to detect a new image.
If the device is unplugged and then plugged in again too soon, it will not be able to collect enough high quality entropy. In this case it will refuse to generate a wallet and indicate this by flashing a series of three blinks. Please wait a few seconds between removing and re-inserting your device.
To create a 2-of-3 split key wallet, briefly press the button right after inserting the device into your printer. This will create a Bitcoin address with a private key that is split into 3 parts, requiring a combination of any 2 of them to be able to spend from it. To make another one, double-click the button. You can use Mycelium Wallet’s Cold Storage function to spend from these wallets.
A number of printers have been tested for compatibility. They are listed in [Appendix A: Printers].
For technical information about Mycelium Entropy and why it is secure, please see Appendix B: How It Works and the source code.