Helium A Decentralized Wireless Network Amir Haleem Andrew Allen Andrew Thompson Marc Nijdam Rahul Garg Helium Systems, Inc. Release 0.4.2 (2018-11-14) Abstract to affect. These networks are more complicated to decentral- ize as they often require specialized hardware to function. The Internet of Things is an $800 billion industry, with over The Helium network is a wide-area wireless networking sys- 8.4 billion connected devices online, and spending predicted tem, a blockchain, and a protocol token. The blockchain runs to reach nearly $1.4 trillion by 2021 [1]. Most of these on a new consensus protocol, called the Helium Consensus devices need to connect to the Internet to function. However, Protocol, and a new kind of proof, called Proof-of-Coverage. current solutions such as cellular, WiFi, and Bluetooth are The Miners who are providing wireless network coverage in a suboptimal: they are too expensive, too power hungry, or too cryptographically verified physical location and time submit limited in range. proofs to the Helium network, and the Miners submitting the The Helium network is a decentralized wireless network best proofs are elected to an asynchronous byzantine fault tol- that enables devices anywhere in the world to wirelessly erant consensus group at a fixed epoch. The members of the connect to the Internet and geolocate themselves without consensus group receive encrypted transactions submitted by the need for power-hungry satellite location hardware or other Miners and forms them into blocks at an extremely high expensive cellular plans. Powering the Helium network is transaction rate. In addition to the blockchain protocol, the a blockchain with a native protocol token incentivizing a two- Helium Wireless protocol, WHIP, provides a bi-directional sided marketplace between coverage providers and coverage data transfer system between wireless Devices and the In- consumers. With the introduction of a blockchain, we inject ternet via a network of independent providers that does not decentralization into an industry currently controlled by rely on a single coordinator, where: (1) Devices pay to send monopolies. The result is that wireless network coverage & receive data to the Internet and geolocate themselves, (2) becomes a commodity, fueled by competition, available Miners earn tokens for providing network coverage, and (3) anywhere in the world, at a fraction of current costs. Miners earn fees from transactions, and for validating the integrity of the Helium network. Our secure and open-source primitives enable developers to build low-power, Internet-connected devices quickly and Note: This whitepaper represents a continuous work in cost-effectively. The Helium network has a wide variety of progress. We will endeavor to keep this document current applications across industries and is the first decentralized with the latest development progress. As a result of the on- wireless network of its kind. going and iterative nature of our development process, the resulting code and implementation is likely to differ from what is represented in this paper. 1. Introduction We invite the interested reader to peruse our GitHub repo The world is becoming decentralized. A multitude of plat- at https://github.com/helium as we continue to open- forms, technologies, and services are moving from central- source various components of the system over time. ized proprietary systems to decentralized, open ones. Peer- to-peer networks such as Napster (created by one of our 1.1 Key Components founders Shawn Fanning) [2] and BitTorrent paved the way for blockchain networks and crypto-currencies to be built. The Helium network is built around the following key com- Now Bitcoin, Ethereum, and other blockchain networks have ponents: shown the value of decentralized transaction ledgers. Exist- ing Internet services such as file storage, identity verification, Proof-of-Coverage We present a computationally inexpen- and the domain name system are being replaced by modern sive Proof-of-Coverage that allows Miners to prove they blockchain-based versions. While software-level decentraliza- are providing wireless network coverage. We anchor these tion has moved quickly, physical networks are taking longer proofs using a Proof-of-Serialization that allows miners 1 to prove they are accurately representing time relative to • Miners join the network by asserting their satellite-derived others on the network in a cryptographically secure way. location, a special type of transaction in the blockchain, and staking a token deposit. Helium Network We demonstrate an entirely new purpose- built blockchain network built to service WHIP and pro- • Miners specify the price they are willing to accept for vide a system for authenticating and identifying devices, data transport and Proof-of-Location services, and Routers providing cryptographic guarantees of data transmission specify the price they are willing to pay for their Device’s and authenticity, offer transaction primitives designed data. Miners are paid once they prove they have delivered around WHIP, and more. data to the Device’s specified Router. Helium Consensus Protocol We present a novel consensus • Miners participate in the creation of new blocks in the protocol construction that creates a permissionless, high blockchain by being elected to an asynchronous byzantine throughput, censor-resistant system by combining an asyn- fault tolerant consensus group. chronous byzantine fault tolerant protocol with identities • Miners are rewarded with newly minted protocol tokens presented via Proof-of-Coverage. for blocks that are created while they are part of the WHIP We introduce a new open-source and standards- consensus group. compliant wireless network protocol, called WHIP, de- • A Miner’s probability of being elected to the consensus signed for low power Devices over vast areas. This pro- group at a given epoch is based on the quality of the tocol is designed to run on existing commodity radio wireless network coverage they provide. chips available from dozens of manufacturers with no proprietary technologies or modulation schemes required. • The blockchain employs Proof-of-Coverage to guarantee that Miners are honestly representing the wireless network Proof-of-Location We outline a system for interpreting the coverage they are creating. physical geolocation of a Device using WHIP without the [Figure 1] shows a visual representation of the Helium need for expensive and power-hungry satellite location network. hardware. Devices can make immutable, secure, and verifiable claims about their location at a given moment in time which is recorded in the blockchain. 2. The Helium DWN DWN We present a decentralized wireless network (DWN) We introduce the core conmponents of the DWN. that provides wireless access to the Internet for Devices by way of multiple independent Miners and outlines the 2.1 Participants Helium network and WHIP specification by which par- ticipants in the Helium network should conform. Routers There are three types of participants in the Helium network: pay this network of Miners for sending data to and from Device, Miner, or a Router. the Internet, and Miners are rewarded with newly-minted tokens for providing network coverage and delivering De- Devices send and receive encrypted data from the Internet vice data to the Internet. using hardware compatible with WHIP [Section 2.4]. Data sent from Devices is fingerprinted, and that fingerprint stored in the blockchain. 1.2 System Overview Miners provide wireless network coverage to the Helium • The Helium network is a decentralized wireless network network via purpose-built hardware, called Hotspots [Sec- built around WHIP on a purpose-built blockchain with a tion 2.5], which provide a long-range bridge between native token. WHIP devices and the Internet. Users join the Helium network as Miners by purchasing or building a Hotspot • Devices take the form of hardware containing a radio chip that conforms to WHIP, and staking a token deposit pro- and firmware compatible with WHIP, and spend tokens portional to the density of other Miners operating in their by paying Miners to send data to and from the Internet. area [Section 5.3.3]. Miners participate in the Proof-of- • Miners earn tokens by providing wireless network cover- Coverage [Section 3] process to prove that they are contin- age via purpose-built hardware which provides a bridge uously providing wireless network coverage that Device between WHIP and Routers, which are Internet applica- can use. Miners join the Helium network with a score tions. [Section 3.3.4] that diminishes as blocks pass without valid proofs being submitted. At a given epoch, a new • Devices store their private keys in commodity key-storage group of Miners are elected to a consensus group which hardware and their public keys in the blockchain. mine new blocks in the blockchain and receive the block 2 Token Exchange Peer-to-Peer GPS GPS/GNSS Authentication Coverage Gateway Gateway Machine Router Token Token Gateway Blockchain Router Figure 1. System Overview reward and transaction fees for any transactions included The blockchain consists of blocks which contain a header and in the block once mined. As a Miner’s score drops their a list of transactions. There are several kinds of transactions, probability of being elected to the consensus group and outlined in [Section 5]. mining blocks diminishes. At a given epoch a given block consists of: Routers are Internet applications that purchase encrypted Device data from Miners. In locations with a sufficient Block Version number of Miners, Routers can pay several Miners to Block Height obtain enough copies of a packet to geolocate a Device Previous Block Hash without needing satellite location hardware, which we call Transactions 1..n Merkle Hash Proof-of-Location. Routers are the termination point for Threshold signature by the current consensus group Device data encryption. Devices record to the blockchain to which Routers a given Miner should send their data, As the Proof-of-Coverage [Section 3] is valuable to the net- such that any Hotspot on the Helium network can send work, Miners are required to submit their proofs at regu- any Device data to the appropriate Router.