Blockchain & Bitcoin FAQ

A blockchain is a shared, append-only ledger maintained by many independent computers. Each new entry (a block) is cryptographically linked to the previous one, so the entire history is tamper-evident. Anyone can verify the data without trusting a central authority.

A regular database has an owner who can change any record at any time. A public blockchain has no single owner; updates require network consensus, and past records cannot be altered without rewriting (and reproducing the proof of work for) every block after them. The trade-off is throughput and flexibility for verifiability and censorship resistance.

No. Public blockchains like Bitcoin and Ethereum are open to anyone. Permissioned or private blockchains restrict participation to known parties and are typically used by enterprises for supply chain, settlement or audit use cases.

Bitcoin is one application of blockchain — the first and most widely used. Blockchain is the underlying data structure and protocol pattern; many other systems (Ethereum, Litecoin, Monero, etc.) use blockchains with different rules.

Bitcoin is a decentralised digital currency created in 2009 by the pseudonymous Satoshi Nakamoto. It uses a peer-to-peer network and a Proof of Work consensus mechanism to allow value transfer without a central issuer or intermediary.

Miners group pending transactions into a candidate block, then repeatedly hash the block header with a changing nonce, looking for a hash below the network target. The first miner to find one broadcasts the block; other nodes verify it and add it to the chain. The miner earns the block subsidy plus transaction fees.

Proof of Work is a consensus mechanism that requires computational effort to add new blocks. This makes the chain extremely expensive to rewrite, because an attacker would have to redo the work for every block they want to change while honest miners keep extending the legitimate chain.

Roughly every four years (every 210,000 blocks), the block subsidy paid to miners is cut in half. This enforces Bitcoin's capped supply of 21 million coins and creates a predictable, decreasing issuance schedule.

The Bitcoin protocol itself has never been broken. Security risks are almost always at the human or service layer — exchange hacks, phishing, lost private keys. Self-custody with good operational security significantly reduces these risks.

Ethereum is a programmable blockchain that supports smart contracts — code that runs on the network and enforces rules without intermediaries. Beyond a currency (ETH), Ethereum hosts thousands of applications in finance, gaming, identity and more.

A smart contract is code deployed to a blockchain that automatically executes when its conditions are met. It enables trust-minimised agreements: once deployed, the rules are public, immutable (unless designed to be upgradeable) and enforced by the network rather than a third party.

On Ethereum and EVM-compatible chains, the dominant language is Solidity. Vyper is a Python-like alternative. Other ecosystems use Rust (Solana, Near), Move (Aptos, Sui) or specialised languages.

Web3 is a broad term for an internet built around user-owned identity, data and assets, typically using blockchains, wallets and smart contracts. In practice it covers decentralised applications (dapps), DeFi, NFTs and on-chain identity systems.

No. Conceptual courses like our Bitcoin 101 are written for any technically curious person. Deeper courses on Proof of Work, signatures and the UTXO model assume comfort with basic programming and arithmetic, but no specific language background.

With focused study, you can develop a solid mental model in 10–20 hours of interactive learning. Mastery — being able to reason about edge cases, attacks and protocol changes — takes longer, but the curve is forgiving once the fundamentals click.

Start with Bitcoin 101 to build vocabulary and intuition. Then take the Proof of Work course to understand how the system actually maintains consensus. From there you can branch into Ethereum, smart contracts and Web3 with a much stronger foundation.

Yes. The core curriculum is free to use. An account is only needed for progress tracking and the personalised dashboard.

A wallet is software (or a hardware device) that manages your private keys and lets you sign transactions. The wallet does not really 'hold' coins — the coins live on the blockchain, and the wallet proves you own them.

A private key is a secret number that authorises spending from a blockchain address. Whoever knows the private key controls the funds. Never share it. Never enter it into a website you do not fully trust.

A seed phrase is a human-readable backup of your wallet's private keys, usually 12 or 24 words. It can restore your entire wallet on any compatible device. Treat it like the master key to a vault: write it down, never store it digitally if you can avoid it, and never share it.

A hardware wallet is a small device that stores private keys offline and signs transactions internally. Because the keys never leave the device, even a compromised computer cannot directly steal them. It is the recommended option for significant balances.

ZeroToBlock is an interactive blockchain education platform. Instead of reading slides, you mine real blocks, verify hashes, sign transactions and observe consensus in your browser. The goal is hands-on understanding, not memorisation.

Certificates are on the roadmap. For now, the focus is on building understanding that transfers directly to real work and interviews.

For non-commercial educational use, yes — with attribution and a link back to the source page. For commercial use, please reach out via the contact page.