Learn About Bitcoin

What is Bitcoin?

Bitcoin is a peer-to-peer electronic cash system that operates without a central authority. Transactions are verified by a distributed network and recorded permanently on a public ledger. No institution can freeze accounts, reverse confirmed transactions, or issue coins beyond the fixed supply of 21 million.

How Does a Bitcoin Transaction Work?

Bitcoin transactions consume amounts you control and create new ones. Learn how inputs, outputs, fees, and confirmation work.

What are Private Keys and Public Keys?

Private keys prove ownership. Public keys enable verification. Learn how the Bitcoin key pair works and why the private key must stay secret.

What is a Bitcoin Wallet?

Bitcoin wallets store private keys, not bitcoin. Learn how they work and the difference between custodial and self-custodial arrangements.

What Gives Bitcoin Value?

Bitcoin derives value from its monetary properties: a fixed supply, no issuing authority, and verification that requires no trust.

What is Bitcoin Self-Custody?

Self-custody means controlling your Bitcoin private keys directly, without delegating that control to an exchange or custodian. When you control the keys, no third party can freeze, seize, or lose your funds on your behalf. When you don't, you own a claim against someone else's balance, not bitcoin itself.

A History of Bitcoin Exchange Failures

Exchange failures have cost Bitcoin holders billions. This article documents the collapses that make the case for holding your own keys.

Bitcoin Security Threat Models

Learn to build a Bitcoin security threat model: what you are protecting, who might threaten it, and what measures are proportionate to the risk.

The Spectrum of Bitcoin Custody Options

Bitcoin custody exists on a spectrum from exchange accounts to air-gapped hardware. Learn what each arrangement means and who controls the keys.

The Risks of Holding Cash in a Bank

Bank deposits carry inflation, counterparty risk, and capital controls. Learn how these structural risks compare to Bitcoin self-custody.

Why Bitcoiners Choose Hardware Wallets

Hardware wallets keep private keys permanently offline. Learn why the distinction between online and offline key storage defines Bitcoin security.

How Bitcoin Wallets Work

A Bitcoin wallet generates and stores private keys, which are the credentials that authorize spending. Bitcoin itself exists as entries on the blockchain, not inside the wallet. The wallet tracks which addresses belong to its keys, monitors the blockchain for incoming funds, and constructs the signed transactions needed to send them.

What is a Bitcoin Private Key?

A private key is a randomly generated 256-bit number from which every Bitcoin address it controls is mathematically derived. Ownership of bitcoin is, at a technical level, possession of the private key. The key is never broadcast to the network; what gets sent is only the cryptographic signature it produces.

What is Public Key Cryptography?

Public key cryptography lets Bitcoin prove ownership without revealing the private key. Learn how key pairs and digital signatures work.

What is a Bitcoin Address?

Bitcoin addresses are derived from public keys. Learn what address formats mean, how generation works, and why address reuse reduces privacy.

What Are Bitcoin Hash Functions?

Learn what hash functions are, why they are one-way, and how Bitcoin uses them across address generation, transaction IDs, and proof of work.

What is a Bitcoin Seed Phrase?

A seed phrase is 12 or 24 words that generates every key in a Bitcoin wallet. Learn how it works and why it is the only backup that matters.

HD Wallets and Bitcoin Derivation Paths

HD wallets derive every key from one seed. Learn how derivation paths work and why the path matters when restoring or recovering a wallet.

What is a Hardware Wallet?

A hardware wallet is a dedicated device that stores private keys in isolated hardware and signs transactions without exposing those keys to any connected computer. The keys are generated on the device and never leave it. Signing happens internally, and only the completed signed transaction is passed back to the host software.

Hot Wallet vs. Cold Wallet

A hot wallet keeps private keys on an internet-connected device. A cold wallet keeps them offline. Learn the difference, the risks of each, and when to use which.

What is Air-Gapped Signing?

Air-gapped signing means the private keys never touch a device with a network connection at any point in the signing process. The unsigned transaction is passed to the signing device via QR code or physical media, the device signs it internally, and the signed transaction is returned the same way. Nothing travels over a network.

What is a Bitcoin Software Wallet?

A Bitcoin software wallet stores your keys on a phone or computer. Learn the types, what threats they face, and when a software wallet is and is not the right tool.

What is Bitcoin Multisig?

Multisig is a Bitcoin spending policy that requires signatures from more than one private key before a transaction can be authorized. No single key can move the funds on its own, so there is no single point of failure for theft or loss. A 2-of-3 multisig requires any two of three keys to sign.

2-of-3 Multisig Explained

A 2-of-3 multisig wallet requires any two of three keys to spend. Learn how to design a quorum, distribute keys, handle key loss, and why 2-of-3 is the most common multisig setup.

Collaborative Bitcoin Custody vs Solo Multisig

Collaborative custody gives a third party one key in your 2-of-3 wallet. Solo multisig means you hold all keys. Learn the tradeoffs: control, complexity, cost, and recovery.

What is a PSBT?

A PSBT is a standard format that separates transaction construction from signing. Learn how PSBTs work, why they matter for hardware wallets, and the difference between BIP174 and BIP370.

How to Store Your Seed Phrase

Storing a seed phrase correctly means writing every word in numbered order during wallet setup, choosing a durable physical medium, making at least two copies stored in geographically separate locations, and verifying recovery before you need it. Paper is adequate for a small spending wallet. A savings wallet requires a metal backup.

Paper vs Metal Seed Phrase Backups

Paper seed backups are free but burn and flood easily. Metal backups survive both. Learn why metal is better for savings wallets and what you need to know before choosing.

How to Choose a Metal Seed Backup

Metal seed backups record characters using three categories of approaches. Learn the criteria that matter and which method fits your setup.

Seed Phrase Storage and Physical Security

Where you store your seed phrase backup is as important as what you store it on. Learn the physical threats to protect against and how to choose the right storage locations.

Bitcoin Inheritance Planning

Bitcoin has no recovery path if keys are lost at death. Learn the four inheritance frameworks and how to choose the right one for your situation.

What is a Bitcoin Passphrase?

A Bitcoin passphrase is an optional word or phrase added to your seed phrase that creates an entirely separate wallet. Learn how it works, why it matters, and its risks.

Common Bitcoin Backup Mistakes

Photographing your seed phrase, storing a single copy, or pairing a passphrase with a seed backup are mistakes that cost Bitcoin holders their funds. Learn what to avoid and why.

Bitcoin Transaction Security

Most self-custody attention goes to seed phrase storage. But every send involves a separate set of security decisions, from address verification to fee selection to how the transaction reaches the signing device.

What is Bitcoin UTXO Management?

Bitcoin has no account balance, only UTXOs. Learn what UTXOs are, why managing them affects fees and privacy, and how to manage them well.

Bitcoin Address Reuse and Management

Reusing a Bitcoin address links all your transactions permanently on-chain. Learn why address reuse hurts privacy and how HD wallets and coin control prevent it.

What is the Bitcoin Mempool?

The Bitcoin mempool holds unconfirmed transactions waiting for miners. Learn how it works, how to read mempool.space, and what to do when a transaction gets stuck.

What are Bitcoin Transaction Fees?

Bitcoin fees are priced per virtual byte, not per transaction. Learn how sats/vbyte works, why SegWit addresses are cheaper, and how to set the right fee rate.

How to Verify Bitcoin Transactions

On-device verification is the last line of defense before a Bitcoin transaction is signed. Learn how to check addresses, amounts, and fees on your signing device before every send, and how to confirm your transaction after broadcast.