How Bitcoin became possible.

Claude Shannon publishes “A Mathematical Theory of Communication,” formalizing information, entropy, and digital communication.

Shannon publishes “Communication Theory of Secrecy Systems,” helping formalize modern cryptographic analysis.

Diffie and Hellman publish a method for establishing shared secrets over open networks.

Rivest, Shamir, and Adleman publish RSA, showing practical public-key encryption and signatures.

Ralph Merkle patents tree-based cryptographic commitments that later become important in distributed systems.

David Chaum proposes blind signatures for privacy-preserving digital payments.

Chaum develops cryptographic electronic cash ideas that separate payment verification from payer identity.

Timothy C. May circulates “The Crypto Anarchist Manifesto.”

David Chaum founds DigiCash to commercialize cryptographic electronic money.

Eric Hughes, Timothy C. May, John Gilmore and others help form the cypherpunk community and mailing list.

Eric Hughes publishes “A Cypherpunk’s Manifesto,” emphasizing privacy through deployed cryptography.

Adam Back introduces Hashcash proof of work as an anti-spam mechanism.

Wei Dai proposes b-money, an anonymous distributed electronic cash system.

Nick Szabo develops the Bit Gold concept around costly-to-create, linked digital objects.

Hal Finney launches Reusable Proofs of Work, making proof-of-work tokens transferable through trusted hardware.

Satoshi Nakamoto publishes “Bitcoin: A Peer-to-Peer Electronic Cash System” on October 31.

Satoshi mines Bitcoin block 0 on January 3.

Bitcoin v0.1 is released and the network begins operating publicly.

Satoshi sends bitcoin to Hal Finney in the first well-known person-to-person Bitcoin transaction.

Laszlo Hanyecz trades 10,000 BTC for two pizzas.

Satoshi gradually transfers responsibilities and withdraws from public participation.

Bitcoin gains wider attention through use on Silk Road, intensifying debate around censorship resistance and illicit use.

The block subsidy falls from 50 BTC to 25 BTC.

Specialized ASIC hardware rapidly becomes dominant in Bitcoin mining.

The Mt. Gox exchange collapses, becoming a defining lesson in custodial risk.

Joseph Poon and Thaddeus Dryja publish the Lightning Network paper.

The block subsidy falls from 25 BTC to 12.5 BTC.

Bitcoin Cash splits from Bitcoin amid the scaling dispute.

Segregated Witness activates on Bitcoin.

The proposed SegWit2x hard fork is abandoned after failing to achieve broad consensus.

Lightning implementations begin broader mainnet use and interoperability.

The block subsidy falls from 12.5 BTC to 6.25 BTC.

El Salvador becomes the first country to make Bitcoin legal tender.

Taproot activates, introducing Schnorr signatures and new scripting capabilities.

Ordinals and inscriptions create a new wave of demand for Bitcoin block space.

The SEC approves rule changes enabling multiple spot Bitcoin ETPs to begin trading in the United States.

The block subsidy falls from 6.25 BTC to 3.125 BTC.

The Runes protocol launches around the 2024 halving, adding another token-related use of Bitcoin block space.

The White House establishes a Strategic Bitcoin Reserve for government-held bitcoin.

Bitcoin continues operating as a global monetary network while institutions, companies, funds, developers, miners, and sovereign actors deepen participation.