A <a href="/glossary/centralized-exchange/">centralised exchange</a> holds customer money and plugs into the banking system, which puts it in the same category as other financial businesses: it is expected to know who its customers are, screen them against sanctions lists and report suspicious activity. Verification is how it does that. Banking partners generally insist on it too, which is why the fiat on-ramp is almost always where documents get requested.
In practice you meet KYC as tiers. A basic level might unlock small deposits, while larger withdrawals, bank transfers or certain products need fuller documentation. Verification can take minutes or days, and mismatched details — a shortened name, an old address, a blurred scan — are the usual cause of rejections. It is worth completing the step calmly in advance rather than during an urgent withdrawal.
The trade-off deserves naming plainly. Once you verify, your trades and withdrawal addresses sit alongside your legal identity in that company's records, and those records are a tempting target. Any database of IDs and selfies can be breached, and copies of leaked documents do not expire. That is an argument for preferring services that store as little as they can, not a claim that verification is optional.
A <a href="/glossary/decentralized-exchange/">decentralised exchange</a> asks for no documents, but it also offers no account recovery, no support desk and full responsibility for your own keys. Requirements vary by country and by provider, so the service's own terms and a qualified professional are the right sources for your situation — not a glossary. If you do use a verified exchange, keeping long-term holdings off it is a separate habit: our walkthrough on <a href="/toolkit/how-to-move-crypto-off-an-exchange/">moving crypto off an exchange</a> covers the mechanics.
How to Buy Your First Crypto Safely
Key takeaways
- Verification is usually demanded at the boundary with ordinary money — deposits, withdrawals, card payments — rather than at the moment you place a trade.
- Finish verification before you need it, because doing it under time pressure is how people mistype details and get locked out.
- Assume any identity documents you upload could one day be exposed, and favour providers that ask for the minimum they need.
KYC — frequently asked questions
Can I use crypto without ever doing KYC?
Self-custody wallets and on-chain protocols do not ask for identity documents, so parts of the ecosystem work without verification. Converting to or from ordinary currency is where it almost always appears, because that step runs through the banking system. Rules differ by country and by service, so read the provider's terms and speak to a qualified professional about your own circumstances.
Why does an exchange want a selfie as well as an ID?
The photo is a liveness check: it is meant to show that the person submitting the document is the person shown in it, rather than someone who found or bought a scan. Banks use the same logic for remote account opening. It also means the company now stores a biometric image of you, which is one more reason to prefer providers with clear data-retention policies.
Related terms
Centralised Exchange (CEX)Decentralised Exchange (DEX)Fiat CurrencyWalletCustodial All terms →New to crypto, or filling in the gaps? Work through the essentials in Learn, browse every term A–Z, or see live prices for the coins these concepts power.