What does the Bitcoin white paper say?

The Bitcoin white paper is the short document that first described bitcoin. Titled Bitcoin: A Peer-to-Peer Electronic Cash System, it proposes online payments that go directly from one person to another without passing through a bank or other financial institution. It runs to just nine pages.

Who wrote the Bitcoin white paper?

The paper is signed by Satoshi Nakamoto, a pseudonym. Nobody has proved who used the name, a question covered in our guide to who created bitcoin. The paper lists bitcoin.org as its website, and that site still hosts the original English PDF along with translations into roughly 49 languages, including Braille.

When was the Bitcoin white paper published?

Satoshi announced it on October 31, 2008, in an email to a cryptography mailing list with the subject Bitcoin P2P e-cash paper. The email summed up the design: a peer-to-peer system with no trusted third party, protection against double spending, no central mint, and participants who need not reveal their identities.

What is in a Bitcoin whitepaper summary?

The paper has an abstract, 12 numbered sections and a short list of references. Its main points are:

1. The problem. Online payments rely on trusted institutions, which must mediate disputes. Satoshi argued this raises costs and rules out very small payments.
2. Double spending. A digital coin can be copied, so something must prove it was not already spent. The usual answer is a central mint. The paper's answer is to announce every transaction publicly and have the network agree on one history.
3. Timestamp server. Transactions are grouped into blocks, and each block's hash includes the previous one, forming a chain. The paper never uses the single word blockchain, as our guide to crypto vs blockchain notes.
4. Proof of work. Based on Adam Back's Hashcash, it makes adding a block costly. Changing an old block would mean redoing its work and all the work after it.
5. Incentive. The first transaction in each block creates new coins for whoever made the block, and transaction fees can be added. The paper says the reward could eventually rely entirely on fees. Our guide to what happens when all bitcoin are mined covers that future.
6. Privacy. Every transaction is public, so privacy comes from keeping public keys anonymous. The paper suggests a new key pair for each transaction.
7. Calculations. It shows that an attacker's chance of rewriting history falls quickly with each new block, as long as honest participants hold most of the computing power. An attacker with a majority of that power is the scenario known as a 51% attack.

Other sections explain how old data can be pruned to save disk space, how lightweight wallets can check payments using only block headers, and how transactions combine and split amounts, with change returned to the sender.

The paper ends by describing a system for electronic transactions that does not rely on trust. Nodes vote with their computing power, accepting valid blocks by building on them and rejecting invalid ones. Bitcoin.org still calls the document recommended reading for anyone studying how bitcoin works.