5 Unexpected Payment Trends That Could Take 2025 by Storm
Dmytro Spilka·4 min

Double-Spend Attack would allow Alice to spend the same Bitcoin to pay Bob and Carol.
In this case, what is absent from the system is cryptography to secure the transaction and a consensus mechanism to verify it. This brings about a system of verification to check for double-spending using a decentralized network of trustless computers called nodes. The data is then written to a public ledger database that is what you call a blockchain. It effectively resolves the problem with double-spends. Now it is still possible to launch a double-spend attack, but due to the blockchain, it makes it more difficult and costly to do so.
The blockchain is a data structure that is a distributed database that is linked by cryptographic hashes. It is different from traditional databases in its design and purpose. It stores data for the purpose of verification that can be used as a single source of truth.
In the PoW consensus mechanism, nodes called “miners” compete to validate a block by trying to solve difficult cryptographic puzzles. The miner who gets the correct answer, called the nonce, will validate the block and in return get a reward for it. Bitcoin uses a difficulty target that determines how quickly the nonce can be solved based on total hash power in the network. The difficulty increases with the total amount of hash power available on the network. The increase in the hash power is directly proportional to the number of miners on the network. The difficulty increases in order to slow down the rate of block-creation. This is done in order to prevent consuming all the supply of Bitcoin. It is possible for a bad actor with a majority of the hash rate (i.e. a powerful computer) to quickly mine blocks to collect the rewards. Therefore the algorithm will adjust by making it more difficult to mine and allow other miners a chance at solving for the nonce.
Calculating the nonce expends a lot of electricity, which is what critics call inefficient. According to Bitcoin evangelist Andreas Antonopoulos, this is not a waste of energy but rather a part of the production process that creates Bitcoin. Just like you expend energy to extract gold from the ground, energy, in this case, is being spent to produce Bitcoin. That is where the value lies and the miners get a reward in return for their computing contribution and securing the network. When looking at where many miners get their electricity sources though, they are actually green and renewable sources (Read this report link from Coinshares). In Iceland, miners use geothermal power for bitcoin mining. Other sources of electricity include hydrothermal and solar power. The process is rather long to explain, but it is basically how transactions on a Bitcoin payment network are verified.
A seller cannot cheat the buyer by pretending they did not receive a payment and vice versa. This is because the truth is recorded on the blockchain database, and made immutable and transparent for all to see. The blockchain acts as a public ledger that can corroborate Alice paid Bob, and Bob received his payment. There is a consensus among trustless nodes, who don’t have to know each other. This helps to eliminate any sort of collusion which is more likely to occur in trusted systems because it is centrally controlled.
The blockchain was meant to be the opposite, so that is where it builds trust. In other words, every part of a transaction must act in good faith or else there will be consequences. If a bad actor tries to double spend, they will realize that it costs more to attack the network so they would rather mine in good faith. The transparency discourages dishonesty since it is made available to the public and no one can tamper with the transaction once it has been added to the blockchain. Thus, Bob cannot say that Alice didn’t pay him because if we use a block explorer it can track the transaction to show proof of payment.
You can only have at most 2 out of the 3 properties of a blockchain, which is decentralization and security. When you have those two, you cannot achieve scalability. This can be shown by the diagram for the “Scalability Trilemma” theory (Bitcoin example).
When you have more decentralization, you have greater security as well but you will have to sacrifice scalability.
When you have less decentralization, you have scalability but with less security too.
Decentralized systems bring a more distributed architecture to the network. There is no single point of failure, thus it is more redundant and secure. If any node goes down in the network, it does not affect the entire system. The system can continue to function as a whole. Think of the Internet as a decentralized network. When one server on the Internet is attacked, there are still other servers that keep the network up and running.
In a blockchain, if a node that stores a transaction in a block is attacked, it does not matter. Other nodes store a copy of the block so it keeps the network secured because now all the other nodes have to be attacked as well. When you have thousands of nodes, it makes the task more difficult since it requires more computing resources to accomplish. That in effect can prove to be more expensive. Despite being more secure, the system is slower. This is like having too many cooks in the kitchen having to agree on what to cook. In this case, the more nodes you have, the longer it takes to come to a consensus to verify transactions and that slows the system down.
In a centralized system, you achieve scalability faster because you don’t require trustless nodes that duplicate the same data. You have trusted nodes in which one server can quickly perform a task. You process transactions faster and at scale because since you have only one decision-maker that is a trusted system. Centralization means there is more control and cohesion. When verifying transactions, a trusted system can do it right away because it doesn’t need to come to a consensus with other nodes.
There is a single point of failure however, so if the system is compromised then everyone who is a part of the system will be affected as well. This is what happens with traditional financial systems that are heavily centralized. Banks and other financial institutions are fine examples of this. They can also block transactions at any time and ban users from their system because they control it.
It is nice to have all three components in a blockchain, but it just seems to be impossible to do. There are proposed scaling solutions but perhaps that is more on innovation. Going back to the purpose of a blockchain, it seems that Bitcoin has been accomplishing things all along. Since its genesis block in 2009, Bitcoin has been proving it is an example of a mature technology that has withstood time and proven its value. So why is it slow, like the critics say?
Without that layer of calculation, spam attacks could be more common on the network because there is nothing to discourage it. If consensus did not involve the use of solving complex mathematics, then attacking the network would be easier for bad actors. The process behind PoW is to discourage bad behavior and encourage cooperation through the incentives in rewards. It makes it more profitable to mine than it is to attack the network.
Modifying it just so it becomes faster is not based on best practices because you don’t have any way of knowing whether it will be more secure when it comes to the network. When the outcome is vague, you are better off with what already works. It is slow, but it surely achieves its purpose.
The scaling issue is being addressed by core developers working in the Bitcoin community. What makes decentralization so great is that anyone who wants to contribute is welcomed. You have a community that comes together through their common interest to find ways of solving problems.
The scaling issue had proposed solutions like SegWit and the Lightning Network. SegWit has already been implemented through BIP 141 and the Lightning Network has been undergoing many tests. While Bitcoin itself will remain the same, the scaling solutions are meant to be implemented “off-chain” or as “sidechains”. This involves moving the computation layer off the blockchain by using a Layer 2 solution. Sidechains will still have a Merkle Root for provability that they are a part of the same blockchain.
I am a network engineer and technology writer, with a deep focus in blockchain and machine learning technology. I have extensive experience in the IT industry developing and implementing solutions in various industries. I eventually became more interested in blockchain due to the rise in cryptocurrency like Bitcoin. I realized that it was not about speculating on price value, it is a disruption in the finance industry. At the moment I like to educate about the significance of cryptocurrency, which I feel has great potential to drive innovation not just in financial systems, but even in settlements and trust.