What is the Lightning network and how does it work?

The protocol Lightning Network, is a protocol designed to improve the scalability of Bitcoin. This is possible because it works as a second layer on top of Bitcoin which allows you to do things you normally couldn't and more specifically; instant transactions with very low commissions.

The development of this protocol began with the work of Joseph Poon y Thaddeus Dryja. But today they are companies like Blockstream, Lightning Labs y AT FIVE those who promote its development. The whitepaper of this development can be found in that link from its main website.

To understand a little of the potential of this technology, we must keep in mind two things. The first is that Bitcoin was created as a digital money solution. The second is that That goal is impossible to achieve with the current state of the Bitcoin network and software.The reason for this is very simple: Bitcoin is having trouble scaling.

Today, Bitcoin can only process 7 to 8 transactions per secondThis is a very small capacity and cannot cope with massive use. As a result, The Bitcoin network is slow and very expensive when it comes to paying commissions.

For this reason, a new way of making transactions quickly was needed, one that was easy to use and compatible with Bitcoin without having to make major modifications. The answer to these needs is the Lightning Network.

Why do you need to improve Bitcoin's scalability?

Bitcoin is the most robust network on the planet, but its original design prioritizes security and decentralization over speed. If everyone in the world tried to move their tokens directly on the main chain, the system would collapse. Does this mean the protocol is useless? Not at all. It simply indicates that we can't use a heavily fortified highway to go buy bread around the corner.

When the network becomes saturated, transactions pile up in the mempoolThis digital "limbo" is the battleground for miners, who, naturally, prioritize transactions that pay the highest rates to maximize their profits. If you're in a hurry, you pay more. If you're not, you wait. The problem arises when the cost of moving your digital assets exceeds the value of what you're sending.

Paying a five-euro fee for a three-euro transfer makes no economic sense. This scenario completely negates Bitcoin's usefulness for micropayments or everyday mobile transactions. Scaling the network isn't a technical whim, but the only way for this system to move beyond being merely a static store of value and become a functional financial tool for daily life.

Today, solutions like the Lightning Network and new Layer 2 protocols have shown that you don't need to overload the base chain to operate efficiently. Improving scalability allows the ecosystem to breathe, lowering the barriers to entry for the average user. Ultimately, it comes down to deciding whether we want an elite system or a global infrastructure that anyone can use without breaking the bank.

How does Lightning Network work?

The Lightning Network is not a magic bullet; it's a cryptographic construct that relies on the robustness of the main network. For this system to function, data immutability must be absolute.

Before the implementation of followedBitcoin suffered from transaction malleability, a design flaw that allowed for slight alteration of a transaction's identifier before confirmation. Could we build a fast payment network on a foundation that allows for changes to receipts mid-transaction? Clearly not.

By solving this problem, Bitcoin enabled signed but unissued transactions to be secure. This opened the door to payment channels, allowing two parties to interact off-chain without fear of one deceiving the other. This isn't a new network, but rather an intelligent execution layer that leverages the security of the base network to resolve disputes only when absolutely necessary.

Anatomy of payment channels: Much more than a financial chat

If we visualize a payment channel, we should imagine it as a shared custody agreement. Technically, it's a multi-signature address where both participants deposit a certain amount of cryptocurrency. For any transaction to be valid, both must affix their digital signature. It's a mutual veto system: nothing happens unless both parties agree.

• Opening and closing: Only the beginning and end of the channel are permanently recorded on the blockchain. Everything that happens in between is private and fast.
• Status updateEach time you send a fraction of your token to your counterpart, you both sign a new balance that overwrites the previous one. It's like keeping track of accounts on a napkin that you both constantly validate.
• Final settlementWhen you decide you've traded enough, you close the channel. At that point, the main network receives a single final snapshot of the resulting balance.

This mechanism allows thousands of transactions per second without crashing the main network. Does it really make sense to record in a global, immutable ledger that you just paid for a two-euro coffee? Surely not. The Lightning Network solves this dilemma by allowing the main network to be reserved for large settlements, while the everyday flow of digital assets flows through these side networks almost free of charge and instantaneously.

Explaining step by step how the Lightning Network works

To understand how crypto assets flow in this second layer, we need to stop thinking about traditional bank transfers and start thinking about a system of interconnected cryptographic guarantees. The exercise you propose is the classic "routing" scenario, and that's where the real magic of scalability in 2026 lies.

Anatomy of the process: From the individual channel to the global network

Let's imagine that Carmen and Aitor decide to interact. They don't need the whole world to know about their agreement. They open a channel by injecting €20 (€10 each) into a multi-signature contract. This money is "locked" on the main blockchain, but available to move instantly between them on layer 2.

However, the real potential emerges when we connect these channels. If Carmen wants to pay David but doesn't have a direct line to him, the network finds a way. It leverages the fact that Carmen knows Aitor, Aitor knows Laura, and Laura knows David. The funds don't physically "travel" as a package; what happens is a chain reaction of balance adjustments:

• Carmen gives the value to Aitor within her private channel.
• Aitor, in exchange for a minimal commission, gives that value to Laura.
• Laura does the same with David.

How do we prevent Aitor from keeping the money and disappearing? This is where the... Hashed Timelock Contracts (HTLC)It's a smart contract structure that makes payment contingent on the presentation of a mathematical "secret." If the payment doesn't reach its final destination within a specified time, the funds are automatically returned to their origin. There's no need to rely on intermediaries; mathematics does the dirty work.

Clearing the unknowns of the system

You've raised three questions that resonate deeply with any security analyst in the digital asset sector. Let's dissect them pragmatically.

How is it possible to trust routing?

You don't trust them. Period. The protocol uses a "riddle and key" system. David generates a secret code and sends only the trace (the hash) to Carmen. Carmen sends the money into the network wrapped in that lock.

Each person on the route can only collect their share if they present the key, which David will release only after receiving his tokens. If anyone in the chain tries to cheat, the contract expires and the money reverts to Carmen. It's a brilliant passive security system.

What about availability?

This is the Achilles' heel for some. To receive or send Lightning payments, your node or mobile device must be online to sign channel updates. If David's computer is off, Carmen can't complete the payment directly.

However, by 2026, Lightning Service Providers (LSPs) and persistent cloud nodes have mitigated much of this drawback, allowing for an experience almost identical to that of a conventional payment app.

How do you combat deception?

What happens if Aitor tries to close the channel with Carmen by posting an old balance sheet showing him with more money? The protocol severely punishes fraud. There is a "challenge period." If Carmen discovers that Aitor has uploaded an old image of the account to the blockchain, she can initiate a legal action.

The result? The protocol hands over all the channel's funds to Carmen, including Aitor's, as a penalty for attempted theft. It's such an aggressive financial incentive that trying to cheat the network is usually a quick way to lose your assets.

How is it possible to trust step 3?

In reality, Aitor and Laura act as nodes within the network, similar to miners in the Bitcoin network. This is because they process all transactions in a decentralized manner without having control over the funds they help move.

For that reason, Aitor and Laura could never steal Carmen's funds since the funds to be sent will only be received if the outgoing transaction to the final recipient, which in this case is David, has already been carried out.

What about availability?

If Aitor disconnects, the channel's funds wouldn't be trapped indefinitely. Within the Lightning Network's smart contract mechanism, users can unilaterally close channels. Therefore, if Aitor were to disappear, Carmen could recover her money thanks to the time attribute added to the contract.

When a channel is closed simultaneously after an indefinite number of trades have been made on it, the final funds of each party will be recorded on the blockchain for 10 minutes or as long as it takes for the next block to appear.

How do you combat deception?

If Carmen sends funds from her multi-signature address to David on the Lightning Network, but fails to comply and instead issues an old transaction on the blockchain to close the channel in the state it was in before sending the transaction to David, the software itself, designed to detect this type of action, will cause Carmen to lose all the funds she sent to David. This is a penalty for such an action, so anyone who attempts to transmit an old and invalid transaction will be penalized.

Thanks to this network of person-to-person channels, it is possible to find a pattern within the network through which transactions can be transmitted outside the blockchain without limits. All this, without losing the confidence that later and after the channel is closed, it will be recorded within the Bitcoin blockchain.

Lightning Network Security

Regarding security, there is a paper published in 2019 that carries out a rather technical analysis on the robustness of this development.

The authors, Aggelos Kiayias (IOHK and University of Edinburgh) and Orfeas Stefanos Thyfronitis Litos (IOHK) performed a thorough review of Lightning network security and the result of it is a document of 84 pages that you can consult and download by clicking on the following image.

Click on the image to download the document

Advantages and disadvantages of the Lightning Network

Advantages

1. First of all, Lightning offers one of the most powerful options to improve Bitcoin's scalability. Lightning can take Bitcoin up to levels close to 1 million transactions per second, much more than those managed by payment systems such as Visa o MasterCard.
2. It offers high levels of security and anonymity. This is because transactions occur off-chain making payments virtually impossible to trace.
3. lightning It is compatible with other projects besides Bitcoin. For example, it is possible to use Lightning with Litecoin.
4. It is capable of greatly reducing the level of transaction traffic within the Bitcoin network. This would make the network run much more efficiently.
5. Transactions using the Lightning Network are done almost instantly.
6. It allows the realization of micropayments and even allows their automation.
7. Enables the ability to perform atomic swaps Cross-chain. This allows two blockchains that use the same hash function to exchange tokens without the need for an intermediary such as a exchange.

Disadvantages

1. One of the main disadvantages of Lightning is that payments can only be made to users who are connected to a payment channelThis means that the user must be active and connected to the channel. Unlike this, traditional transactions do not have this limitation.
2. The Lightning Network is a protocol that is in constant development. Proof of this is that its creators still recommend not using Lightning for operations with large sums of money.
3. The protocol limits the channel's liquidity to the total number of tokens held by all parties.This is another situation that undermines high-value operations, as it leads users to divide their funds to have liquidity in the normal blockchain and in Lightning channels.

FAQ – What is the Lightning Network and how does it work?