Darkwire Enables Bitcoin Transactions Without Internet Access

Darkwire, a new open-source project, has developed infrastructure that allows users to send Bitcoin transactions without internet access. Submitted to the Bitcoin 2025 Official Hackathon, this project utilizes long-range radio technology to enable off-grid communication. The project was conceived and designed by a pseudonymous programmer known as 'cyber,' who is currently pursuing a degree in artificial intelligence and machine learning.

Cyber explained that darkwire is particularly useful in situations where traditional communication infrastructure, such as the internet, power grid, or cellular networks, is unavailable or controlled. This includes censored or politically sensitive regions, disaster areas where infrastructure may have been destroyed, and individuals seeking privacy or wishing to bypass surveillance of their communications and transactions. Cyber likened darkwire to Tor but specifically for this use case, addressing the issue of governments and regimes cutting off internet supply.

The framework uses Long Range Radio (LoRa) to create a decentralized mesh network, allowing devices to send small packets of data, such as text messages or Bitcoin transactions, over distances of several kilometers without needing traditional internet connections, cellular networks, or satellites. At least one node in the network needs to be connected to the internet to push the transaction to the blockchain for miners to verify it.

Darkwire also makes use of microcontrollers, such as Arduino UNO, to form a mesh network—a decentralized network in which multiple nodes are connected to multiple other nodes, with no centralized access point. When a user wants to send a Bitcoin transaction using the darkwire GUI, they specify the recipient address and amount using a local wallet managed by bitcoinlib, a Python library. The darkwire graphical user interface then generates a signed raw Bitcoin transaction in hexadecimal format, which is sent from the computer to a darkwire node via a serial connection such as USB. The darkwire node takes this transaction data, fragments it into smaller packets if necessary, and transmits it wirelessly using LoRa.

In ideal conditions, each darkwire node has a range of 10km with direct line of sight, although in more densely populated environments the range would be between 3km and 5km. In the mesh network, other darkwire nodes receive these packets and relay them forward, hopping from node to node until the transaction data reaches a designated darkwire node that does have internet access. This internet-connected node acts as an exit point, broadcasting the collected and verified raw Bitcoin transaction onto the global Bitcoin network, where it can then be included in a block.

Currently, darkwire remains an entry in the Bitcoin 2025 Official Hackathon, but cyber aims to develop the project further, refining it into a mature open-source platform and making it the industry standard in LoRa-based communications. Cyber noted that several features, such as UTXO retrieval for messages, encryption for messages, and uploading to Nostr, have yet to be implemented. The programmer also acknowledged that darkwire currently has limitations, including the relatively low bandwidth of LoRa radio, LoRa’s sensitivity to terrain obstacles, and the dependence of darkwire nodes on internet exit nodes that could become points of failure. However, as darkwire networks grow, these limitations should be significantly improved, providing Bitcoin users in less favorable environments with the means to send transactions to Bitcoin validators elsewhere in the world.

At a time when the world is becoming increasingly authoritarian and undemocratic, darkwire may end up becoming a vital tool in the ongoing use and growth of Bitcoin. Cyber expressed hope that people living in authoritarian regimes and states would get to use darkwire and put the truth out there.