Lightning Network Explained

The Bitcoin Lightning Network is an autonomous solution that’s signaled as the key to all problems keeping Bitcoin from mainstream implementation. It claims to solve the bleak scaling problem, make instant transactions, keep transaction fees minuscule, and take your transactions off the blockchain.

In this article, we’ll discover what the Bitcoin Lightning Network really is, how it can make the guarantees it provides, and its current state. Bitcoin has a scaling problem. Bitcoin is designed to store all transactions in a data structure called a block. A block contains information about the previous block, miscellaneous data about mining rewards, and most of the block is just transaction data. Blocks are also fixed at a maximum of 1 MB in size. This last bit is where the trouble is.

Because blocks are 1 MB in size, and a block is created every 10 minutes, assuming the transactions are not SegWit (coming up later) the network can process a maximum of between 3.3 and 7 transactions per second. For a currency designed for mass use by billions of humans and their machines, 7 transactions a second just isn’t up to par. Visa, on the other hand, claims to be able to process 24,000 transactions per second.

As the number of transactions starts to increase, your individual transaction competes with every other for inclusion inside a limited block space, and so, the likelihood of having yours included in the block starts to decrease. Since miners can arbitrarily decide which transactions to include in a block, on these occasions, the only way to incentivize the miners to include your transaction is by increasing your transaction fee. However, this starts to make transactions prohibitively expensive — such as this 192 byte transaction for $92.98 where the transaction fee was $14.86.

The Bitcoin Lightning Network

The Lightning Network is a second-layer network that transmits signed, but un-broadcast, transactions among peers and relies on the Bitcoin blockchain only for final settlement of funds. This means that transactions aren’t limited to the block size at all, confirmation times are irrelevant, and the Bitcoin blockchain doesn’t need to store every transaction that ever happens.

Who developed the Bitcoin Lightning Network? It was first described in a white paper authored by Joseph Poon and Thaddeus Dryja but has since evolved into a community effort with third-party individuals and even companies contributing to specifications and implementations.

A Lightning node runs much like and unlike a Bitcoin node in that it operates in a networked fashion, validates transactions, and communicates with other nodes, but it does things that Bitcoin nodes historically do not: it holds funds, act as an automated financial intermediary, actively monitors Lightning “channels” for malicious behaviour and reacts defensively (this is explained in detail later), etc.