Mycelium Announces 'Entropy' Offline USB Paper Wallet Creator

The company has released details on a number of projects, including a USB device that generates paper wallets offline.

AccessTimeIconJul 4, 2014 at 12:30 p.m. UTC
Updated Sep 11, 2021 at 10:56 a.m. UTC

Android wallet provider Mycelium has made announcements on a number of projects this week, including a USB device that offers a unique and more secure way of generating paper wallets for storing bitcoin.

Called Entropy, the USB dongle device allows users to create their paper wallet without an Internet connection being involved at any point of the process.

Look, no web

The small USB device is simply plugged into a compatible printer’s USB port, where it generates a random number with 256-bits of entropy, which is then used to generate a paper wallet with private and public keys.

This wallet is then fed to the printer as a jpeg image file, which is destroyed when the process is complete.

This is what the end result looks like:


The most obvious advantage of this approach is that the paper wallet does not end up on a computer or any device that could be hacked, greatly reducing the chance of having your bitcoin stolen.

adds that Entropy has additional security features:

“This is currently the most secure way to create paper wallets, since the keys are never exposed to the web, use true high level entropy, and only exist on paper. For extra security, Mycelium Entropy can also create M-of-N split keys, where the private key is split up in such a way that you need two out of three parts to spend from an address. In this way, if one of your paper backups is lost or stolen, the thief still can't steal your coins, and you can still access them using the remaining 2 paper backups.”

The company's video explains the basic concept well:

According to Mycelium, the Entropy devices are already fully functional, but need a few software fixes before release.

Furthermore, the company is raising money via an Indiegogo crowdfunding campaign to allow a bigger production run (to bring down the cost of the devices), and because it needs about $1,500 for testing and compliance. About 30% of the necessary funds have been raised so far.

Project updates

In addition to Entropy, Mycelium also provided information on several other projects when it rolled out its new website earlier this week.

– a combination of wallet and payment device – is in the “final stages of development”, the company says, and is nearing completion. The card has been in development for some time and some features eventually had to be scaled down. However, the company indicates it should sell for less than competing hardware wallets.


The Mycelium Payment System is a new and ambitious scheme that allows offline merchants to accept bitcoin with relative ease. The company describes it as a "revolutionary payment system" with no commissions. More details are to be announced soon.

Also new, the Gateway bitcoin ATMis a two-way machine that acts as a gateway that can be used to sync the company's Bitcoincards with the bitcoin network. It allows users to buy or sell bitcoins in just two clicks and should support numerous fiat currencies, including EUR, GBP, USD and many more, according to Mycelium.

There is still no word on a launch date for these projects.


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