Understanding the Technology Behind the Hype

OK, get ready for your brain to start hurting.

When I originally wrote this article, cryptocurrency was introducing an interesting possibility: could people exchange money without relying on a bank to verify and record every transaction?

That question still deserves attention. The suggestion that financial institutions would soon become unnecessary, however, deserves considerably more skepticism.

Let me make my position clear at the outset. I am not a promoter of cryptocurrency, and this article is not a recommendation to buy it. My interest is in understanding the technology, what it accomplishes and where its limitations begin.

After years of developing business software and working with databases, I find the recordkeeping behind Bitcoin particularly interesting. The investment enthusiasm surrounding it is another matter.

So What Is Cryptocurrency?

A cryptocurrency is a digital asset that uses cryptographic techniques to authorize transactions and support the rules of its network.

Bitcoin, which began operating in 2009, was designed to allow electronic payments between participants without requiring a financial institution to act as the intermediary. Its original design was described by someone using the name Satoshi Nakamoto. The original Bitcoin paper

Since then, many other cryptocurrencies have appeared. They do not all work the same way, serve the same purpose or offer the same degree of decentralization.

For this discussion, we will concentrate on Bitcoin. It is complicated enough without inviting every other cryptocurrency into the room.

Start with the Ledger

At the center of Bitcoin is a shared transaction record called a blockchain.

A ledger records transactions. A blockchain organizes those transactions into groups called blocks and links each block cryptographically to the one before it.

Bitcoin’s network uses rules to determine which transactions and blocks are valid. Full nodes independently check those rules. You do not have to operate a full node simply to use a wallet, and every phone or computer using Bitcoin does not carry a complete copy of its history.

One important problem this system addresses is double spending: preventing someone from spending the same digital funds more than once. Bitcoin’s blockchain documentation

So Bitcoin involves a ledger, but it is more than a ledger. It also includes the network, software, transaction rules and digital asset recorded within that system.

That Sounds Familiar

In our inventory control database software, we have long maintained transaction histories that let us reconstruct on-hand balances at earlier points in time.

What came in? What went out? When did it happen? How did we arrive at the balance we see today?

That history is valuable when researching discrepancies, answering customer questions or reviewing an operation.

The similarity to blockchain is the importance of a reliable transaction record. The difference is how that record is controlled.

A conventional business database normally has an organization responsible for administering it. Bitcoin is designed to let participants check a shared record without depending on one central database administrator.

That is an interesting engineering problem. It does not mean that every inventory system, accounting application or business database needs a blockchain.

For many business applications, a conventional database with appropriate permissions, transaction controls and backups remains a practical approach.

How Does Mining Work?

Bitcoin uses a process called proof of work.

Miners assemble candidate blocks of transactions and compete to produce a result that meets the network’s difficulty requirement. Other network participants validate the resulting block before accepting it.

The successful miner can receive newly created bitcoin, called the block subsidy, along with transaction fees.

Bitcoin targets an average interval of approximately ten minutes between blocks. That is an average, not a schedule or a guarantee that a payment will finish in ten minutes. Mining difficulty adjusts every 2,016 blocks to help maintain that pace. Bitcoin’s mining documentation

My original article referred to a subsidy of 25 bitcoin per block. That figure is now well out of date.

Following the April 2024 halving, the subsidy became 3.125 bitcoin per block. Under the existing rules, it halves every 210,000 blocks, approximately every four years. The next reduction is expected around 2028. Bitcoin’s issuance schedule

Mining has also moved well beyond the idea of downloading software and putting an ordinary office computer to work. Competitive Bitcoin mining generally involves specialized equipment, substantial electricity use, cooling and careful attention to operating costs.

Does This Eliminate the Need for Trust?

It changes where trust is placed.

Bitcoin allows participants to verify transactions through software and shared rules, reducing dependence on a central institution for that particular function.

But people still make decisions about wallets, exchanges, custody services and the security of their devices. If a company holds cryptocurrency on your behalf, you are depending on that company to handle it properly.

If you hold it yourself, responsibility for protecting the credentials that control it falls much more directly on you.

And a valid transaction says nothing about whether the person receiving your payment will deliver what was promised. The network can verify a transfer; it cannot inspect the merchandise or settle every dispute.

“Trustless” is a term frequently used in cryptocurrency discussions. I think it needs that explanation attached.

Is Bitcoin Anonymous?

My original article gave too much weight to the idea that Bitcoin could be as private as someone wanted it to be.

Bitcoin is generally described as pseudonymous, rather than anonymous. Its public transaction record uses addresses instead of displaying names, but addresses and transaction patterns can sometimes be connected to people or organizations.

Once that connection is established, the public history may reveal considerably more than someone expected. Bitcoin’s own privacy guidance emphasizes the visibility and traceability of transactions. Bitcoin privacy guidance

A public ledger is a feature worth understanding before treating it as a private payment system.

Secure Recordkeeping Does Not Guarantee a Safe Purchase

Another distinction matters: the security of a transaction system and the value of an asset are separate questions.

A network can record a transaction correctly while the asset changes dramatically in price. It can also record a payment to a scammer just as correctly as a payment to a legitimate business.

Cryptocurrency payments typically lack the reversal options people associate with credit cards. A refund generally depends on the recipient returning the money. The FTC also warns about fraudulent investment offers and demands for cryptocurrency payments. FTC guidance on cryptocurrency and scams

Technical sophistication does not remove ordinary business risk or make an investment profitable.

What Happened to the Merchant List?

My original article included a long list of businesses reportedly accepting Bitcoin.

I have removed it because those lists age quickly. They can also mix together very different arrangements: direct payments, third-party processing, gift cards and limited experiments.

Buying a gift card with cryptocurrency and then using that card at a store does not necessarily mean the store accepts cryptocurrency itself.

If a business offers a cryptocurrency payment option, the useful questions concern the actual transaction: what currency is being charged, what fees apply, how conversion works and how refunds are handled.

A collection of familiar company names does not answer those questions.

Have Financial Institutions Become Unnecessary?

The story has become more complicated than that early prediction suggested.

In January 2024, the U.S. Securities and Exchange Commission approved the listing and trading of several spot Bitcoin exchange-traded products. Its statement explicitly distinguished that approval from endorsing Bitcoin. SEC statement on spot Bitcoin products

To my mind, that development illustrates how cryptocurrency and traditional financial institutions can become intertwined. An asset designed for direct transfers can also become something people access through brokers, funds and custodians.

Banks also perform functions beyond recording payments, including lending and providing account services. A blockchain does not automatically replace all of those activities.

The more useful question is which financial functions this technology can perform effectively, at what cost and with what tradeoffs.

Why I Still Find It Interesting

My interest remains in the underlying problem: how do participants who do not know one another agree on a transaction history without giving one organization complete control?

Bitcoin presents a working approach to that problem. Understanding it helps explain why blockchain attracted attention in the first place.

Whether a particular business needs that approach is a separate decision. Sometimes distributing control is valuable. Sometimes it adds complexity to a problem that an ordinary database already handles well.

And whether someone should buy cryptocurrency is another question entirely.

I am comfortable being curious about the technology without becoming its promoter. There is plenty here to study, question and discuss.

If your brain hurts a little now, mine does too. At least we have a clearer idea of what we are looking at.