What is a blockchain, really?

A blockchain is a shared ledger: a network checks new entries against common rules. It lets people verify transfers without asking a single company to keep every account.

What problem does a blockchain actually solve?

Money, at its core, is bookkeeping. Your bank balance is not a pile of coins somewhere; it is a line in a ledger your bank maintains, and you trust the bank to keep that line accurate. That works, but it means every payment needs a referee: an institution that holds the books, decides what is valid, and charges for the service.

Digital money without a referee has one famous failure mode: a digital coin is just data, and data can be copied. What stops someone from spending the same coin twice? In October 2008, a pseudonymous author named Satoshi Nakamoto published a nine-page paper solving exactly that: let everyone share one ledger, in public, and make rewriting it practically impossible. That ledger design is the blockchain, and Bitcoin was its first application.

How does it work, concretely?

Picture a notebook with three unusual rules:

• Pages are sealed in order. Transactions are grouped into pages (the “blocks”), and each new page starts with the fingerprint of the previous one: a short code computed from the page’s exact content, where changing a single comma changes the whole code. That is the “chain”: edit one old line and the fingerprint of every later page stops matching. The forgery is not hidden; it is glowing.
• Multiple nodes verify the rules. Their role, number and participation conditions depend on the network. Attack resistance depends on the consensus mechanism and its assumptions.
• Signatures authorize operations. Their scope depends on the account and granted permissions. A key does not describe every token control: its contract or issuer may also impose restrictions.

The notebook lets participants verify a shared history. The analogy has limits: validation rules, data access and protocol changes differ across networks. “Blockchain” does not automatically mean everything is public or nobody governs it.

Who keeps it honest, and what about the energy?

Bitcoin uses proof of work. Miners devote computation to producing blocks, while nodes verify the rules. The mechanism consumes energy; its measured footprint at a given date is separate from how it works.

Ethereum has used proof of stake since 2022. Validators lock up ETH; certain violations can cost part or all of that stake. Security relies on economic commitments and consensus rules without reproducing Bitcoin’s mining mechanism.

When does a shared ledger help?

The choice depends on the problem. Sharing verification among parties has coordination costs. Where one organization can maintain the ledger and answer for mistakes, a conventional database may suffice. Where several parties need a shared, verifiable history, the trade-off changes.

A stablecoin payment shows both the value and limits of the ledger. A token transfer between addresses can be located there. That alone does not prove the issuer’s reserve quality or a recipient’s ability to convert it into their usual currency. The transfer and the asset’s value are separate questions.

Why use a layer 2?

Layer 2 networks seek to reduce transaction costs by processing transactions above Ethereum. Their guarantees depend on their design. Base supported Spliz’s former payments; that experience was removed.

Why it matters

In Spliz’s former payments, a USDC transfer on Base had a reference that could be checked on the network. An expense entry or a repayment recorded outside the app is not that proof. Integrated payments were removed; the distinction between a declaration and a transfer remains useful.

The ledger answers a specific question: which operation was recorded under the network’s rules? The rules, asset and parties still need to be understood.

Understanding the asset on the ledger: stablecoins

Sources

Additional source checked on October 10, 2026

• Satoshi Nakamoto, “Bitcoin: A Peer-to-Peer Electronic Cash System”, the 2008 paper that introduced the design.
• ethereum.org, Energy consumption, the post-Merge reduction (99.988%) and current usage estimates.
• U.S. Energy Information Administration, average annual electricity use of a US home (10,791 kWh in 2022).
• ethereum.org, The Merge, the September 2022 switch to proof of stake.
• base.org, the Ethereum layer 2 used by Spliz’s earlier payments.
• DefiLlama, stablecoin circulation (September 15, 2026).
• Cambridge: introducing the CBECI (2019), background on the Bitcoin electricity consumption index.