The Dangers of low Node Count on a Blockchain

Nodes are validators in a blockchain network that determine the legitimacy of any operation happening within said network. They behave collectively by reaching consensus around this legitimacy. Like a group of mathematicians, each node independently arrives at the conclusion that four plus four indeed equals eight. They then compare this answer with other mathematicians to prove this answer and exclude answers that are anything other than eight.

This process is in part why blockchain technologies are so impressive. They help coordinate a distributed system of computers who may or may not have anything to do with one another. This feature also bolsters security. In order to convince the network of mathematicians that the answer is actually six or seven, for example, a malicious actor would have to convert everyone in the network of this. If these mathematicians are anonymous and placed all over the world, the malicious actor will have a difficult time.

Node Count and the Security of your Blockchain

If we continue with the above-mentioned metaphor, it’s also incredibly difficult to convince a very large group of mathematicians of a false answer. With more eyes and capable minds, it becomes more and more difficult to pass incorrect answers through the network. The same is true for nodes on a blockchain.

The more nodes that are validating the credibility of a series of transactions, the more weight or “truth” these transactions have. It is easy to generate such truth with a lower node count, but as this truth has passed through a far less strenuous validation process the percentage that it is a non-truth or false is slightly higher.

Another example that suits this idea is the process of interviewing a potential job candidate. Google is notorious for having an incredibly rigorous, multi-rung interview process which can take weeks on end before the final interview. Excluding the fact that this is hugely challenging for applicants, it also ensures that a certain standard of quality is met.

By passing applicants through different independent juries and interview styles, Google can be relatively certain that the applicant is a good fit or not for working at the company. Each step of the way, an interviewer independently weighs the strengths and weaknesses of a candidate and at the very end, sometimes after 12 interviews, each interviewer then corroborates their findings with the other interviewers and truth is determined.

Replace the 12-interview process with 9,647, the current node count for Bitcoin, and you begin to understand the level of security the Bitcoin network possesses. For all transactions of value, whether that be $6 or $6 million, each must pass across the eyes of over 9,000 different validators to ensure that the transaction is true.

Such a large node count not only functions as a fine mesh to weed out invalid operations, but it also makes collusion between nodes much more difficult.

The Threat of 51% Attacks

If a majority of mathematicians collectively decide that the answer to four plus four is actually seven, they would likely lose their jobs. But this kind of collusion is very possible in the world of blockchain. If more than 51% of the computers in a blockchain network decide to collude or are under the control of a single entity, they can effectively take control of a network.

This control would likely take the form of a double-spending attack or blocking other transactions in the network. For the uninitiated, a double-spending attack refers to the ability to spend the same crypto multiple times. In the world of finance, it would be like going on a shopping spree and to reuse the same $5 bill over and over again.

Because Bitcoin has so many nodes and a relatively high-distribution of miners all over the world, such an attack is incredibly expensive. At current, it would cost $7.5 billion to purchase enough hardware and an additional $5.1 billion per day to run the hardware and launch an attack.

Such a venture would be incredibly difficult, but that doesn’t mean it hasn’t happened. While some mining pools have come worryingly close to having 51% control, other blockchain networks have suffered this exact fate.

The most recent example of this was the Ethereum Classic (ETC) attack in January 2019. Coinbase made the initial announcement, but the fraudsters were effectively able to convert ill-gotten ETC for cash, rewrite the underlying blockchain, and convince the network that the ETC was never spent. They repeated this process until the total amount stolen reached $1 million.

More importantly, members of the ETC community were slow to identify the attack because there were so few nodes watching the chain for strange activity.

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Stay Safe, Run a Node

As we outlined in a previous post, full nodes and miners are slightly different. Both, however, are incredibly important in creating a robust blockchain network. A full node acts as the eyes that monitor the activity of miners as they mint new crypto coins. They are the arbiters of a network and help provision against things like 51% attacks.

Running a full Bitcoin node is relatively straightforward. Interested parties need simply to go to www.bitcoin.org and download Bitcoin Core. Once downloaded, users will then need to wait until the blockchain has synchronized on your computer, which means downloading the approximate 197 gigabytes (and counting) ledger. From there, you can help support network security as well as having access to a Bitcoin wallet.

As the massive storage space needed to participate can be taxing for most computers, a swath of hardware solutions has emerged to make it even easier. With the AVADA Full Node, all users need to do is plug in the router-sized box and then sync the entire Bitcoin, Ethereum or any other blockchain separate from other devices. The three tiers of AVADO hardware allow for much more fun than just blockchain security, but the AVADO i2 is a great starting point to run a full node and support your favorite crypto project.