Bitcoin — Satoshi Creates Decentralized Money

In plain terms

Paying online normally requires a bank: someone has to keep the ledger of accounts and guarantee that the same sum is not spent twice. Bitcoin removes that trusted third party and replaces it with a public ledger that anyone can copy and verify. Adding a page to it means solving a computational riddle that is deliberately expensive in electricity; rewriting an old page would mean redoing all of that work faster than the entire network combined, which costs far more than the fraud would earn. On 3 January 2009, Satoshi Nakamoto wrote the first page — the Genesis block — and slipped that day's London Times front page into it, serving both as proof of date and as political commentary. None of the building blocks used was new: it was their assembly that held where earlier attempts had failed, and the author himself was never identified.

Discovery

Technical explanation

1. Blockchain structure — Each block contains: an 80-byte header (version, previous block hash, Merkle root of the transactions, timestamp, difficulty target, nonce), and a body holding the transactions. The previous block hash creates a chain: altering an old block would invalidate every subsequent block. Average block size: 1–4 MB (post-SegWit). Target inter-block time: 600 seconds (10 minutes).

2. Proof of Work (PoW) — Miners look for a nonce (32-bit integer) such that SHA-256(SHA-256(header)) < target. The target is adjusted every 2,016 blocks (~2 weeks) to keep the inter-block time at 10 minutes. In 2024, the difficulty required an average of ~4.7 × 10²³ hashes (~470,000 exahashes) per block found. The network's global hashrate exceeds 750 EH/s, i.e. ~750 × 10¹⁸ SHA-256 operations per second — more than any other computing infrastructure on Earth.

3. Transactions and UTXO — Bitcoin uses the UTXO model (Unspent Transaction Output): each transaction consumes unspent outputs and creates new ones. A transaction is valid if: (a) the referenced UTXOs exist, (b) the ECDSA signature (secp256k1 curve) proves possession of the private key, and (c) the sum of the inputs ≥ the sum of the outputs (the difference being the transaction fee). This model makes double spending detectable: a UTXO can only be consumed once.

4. Monetary policy written into the code — The block reward starts at 50 BTC and is halved every 210,000 blocks (~4 years). The last satoshi (10⁻⁸ BTC) will be mined around 2140. The series converges to $\sum_{i=0}^{32} 210000 \times \frac{50}{2^i} = 21,000,000$∑i=032​210000×2i50​=21,000,000 BTC.

Why it worked

Before Bitcoin, every attempt at decentralized digital money had failed, each on a different obstacle:

The intractable problem was "double spending": without a central authority, how do you prevent the same digital token from being spent twice?

Satoshi invented no cryptographic primitive: he combined existing building blocks into a system whose security rests on game theory.

Cheating therefore costs more than playing honestly: to rewrite n blocks, an attacker has to spend more energy than the entire network over n × 10 minutes — a prohibitive cost estimated at ~$20 billion/year for a 51% attack in 2024.

Causal chain

Diffie-Hellman invent public-key cryptography (1976) → RSA (1977) → Chaum proposes blind digital cash (1983) → Haber & Stornetta invent timestamped hash chains (1991) → Adam Back creates Hashcash / Proof of Work (1997) → Wei Dai describes b-money (1998) → Szabo conceptualizes bit gold (1998, publicly described in 2005) → Satoshi publishes the white paper (2008) → Genesis block (2009) → first halving (2012) → Mt. Gox hack / 850,000 BTC stolen (2014) → Lightning Network (2018) → El Salvador adopts BTC as legal tender (2021) → spot Bitcoin ETF approval in the US (Jan. 2024)

Anecdote

The message Satoshi encoded in the coinbase parameter of the Genesis block — "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks" — refers to the London Times front page of 3 January 2009, reporting that Chancellor of the Exchequer Alistair Darling was considering a second bailout for British banks. That message is both a timestamp (proving the block was not mined before that date) and an implicit political manifesto: Bitcoin is born as an alternative to a financial system judged to have failed.

Sources

References verified during the August 2026 fact-check audit: these are the pages
against which this bulletin's claims were checked.

1. BTC/USD exchange rate history in 2025 — Exchange-Rates.org
2. Bitcoin surpasses one billion transactions processed — The Block
3. Bitcoin is no longer legal tender in El Salvador (January 2025) — Digital Watch