Bitcoin without the Internet
October 24, 2018
Bitcoin was designed to be a censorship resistant system that doesn't shut anyone out and that can't be shut down by any individual authority or group. Sounds good, this is very much how the Internet is supposed to work too, but unfortunately this is not exactly the case anymore with the Internet. It is obvious in countries like North Korea, China or Turkey that the Internet is sometimes heavily censored and that you can be shut out completely if a government for some reason doesn't like who you are or what you do. Also, this is not something that happens only in China - recently a Swedish court judged that Swedish ISP:s must block certain sites.
The Internet is of course the base layer that Bitcoin needs to function so if you can't use the Internet, you can't use Bitcoin. For Bitcoin to function as a completely free and open infrastructure for money it would need to find alternative paths for the information to take, independent of the internet.
One project that intends to decrease Bitcoin's dependence on the internet is Blockstream's satellite project that allows anyone to receive the Bitcoin blockchain using a small satellite antenna and a USB receiver. Blockstream's ground stations transmit new blocks to the satellites so that anyone can receive them, even without an internet connection. This makes it possible for anyone to fully validate the Bitcoin blockchain even without internet access and it already covers Europe, Africa, North and South America and more satellites are planned. This is obviously really cool but it is one way communication so it doesn't provide a way to send transactions.
So what about sending transactions without an internet connection? Over the years there have been several creative attempts at sending Bitcoin transactions without using the internet. One way that was tried out already in Bitcoin's early days is to make use of the existing cell phone network and send a Bitcoin transaction as an SMS. Another one is to use APRS ,an amateur radio based communications protocol. More entertaining options include Bitcoin as a message in a bottle. In the end, all of these of course depend on reaching some sort of relay node that can broadcast the transaction to the Bitcoin network for you, using the Internet, but it can provide a way to reach such a node, without having an internet connection yourself.
In an interesting presentation at the recent HCPP18 conference in Prague Richard Meyers introduced TxTenna, a way to send Bitcoin transactions using GoTenna Mesh devices together with Samourai wallet. GoTenna lets you build mesh networks using small devices that can be paired with your phone and that communicate with each other using radio frequencies that are open for the public to use. This means that a Bitcoin tranasction can be travel through a number hops of GoTenna devices until it reaches a device that has an Internet connection.
Combine the retrieval of blocks from satellite with mesh technologies for sending and you actually have a way of using the Bitcoin network, with full validation, without relying on the internet. There are still some obstacles left to get this to be practical and some of them might prove to be hard, such as getting enough users in a mesh network that you can easily find a peer when you need it, but the development is sure interesting.