Crypto Custody: Exchanges, Wallets, and Who Actually Holds Your Keys
Owning crypto is really a question about who controls the keys. The answer determines which risks you carry, and there is no arrangement that carries none of them.
Two models, and the difference that matters
Every crypto holding sits in one of two arrangements. Under custodial holding, a company — usually an exchange or a broker — controls the private keys and maintains an internal ledger recording what it owes you. What you own in that case is a claim on the company rather than the coins themselves, since the coins are generally pooled and recorded on-chain under the company's control. Under self-custody, the keys are generated and held by you, the blockchain records your address as controlling the balance, and no intermediary can freeze it, lend it out, or lose it on your behalf. That distinction is what the phrase not your keys, not your coins actually describes. It is not a slogan about ideology; it is a plain statement about where practical control sits and about who, precisely, you are relying on.
Hot, cold, and the recovery-phrase problem
Within self-custody, wallets are usually described as hot or cold. A hot wallet is connected to the internet — a mobile or browser application, convenient for frequent use and correspondingly exposed to malware, phishing, and fraudulent transaction approvals that a user signs without fully understanding. A cold wallet keeps keys on a device or medium that never goes online, signing transactions in isolation: far more resistant to remote attack, and far less convenient. Both rest on the same foundation, a recovery phrase of typically twelve or twenty-four words that mathematically reconstitutes every key in the wallet. The phrase is the account. Anyone who obtains it can move the funds from anywhere in the world, and anyone who loses it has, in almost all cases, lost the funds permanently. There is no password reset, no support line with override powers, and no way to reverse a transaction once it has confirmed.
- Custodial: convenient, recoverable if you forget a password, and wholly dependent on the company's solvency, controls, and honesty.
- Self-custodial hot wallet: you hold the keys, but an internet-connected device sits in the attack path every time you approve something.
- Self-custodial cold wallet: strongest against remote attack, weakest against your own loss, damage, or forgetting — the failure mode moves from someone else's balance sheet onto your own record-keeping.
Choosing a custody model is not choosing whether to carry risk. It is choosing which risk you would rather be responsible for.
What the 2022 failures demonstrated
The case for taking counterparty risk seriously is not theoretical. During 2022 a series of large centralised crypto firms failed in quick succession: several lenders that had taken customer deposits and redeployed them entered bankruptcy over the course of the year, and in November one of the world's largest exchanges collapsed and filed for bankruptcy, with customer funds unavailable and senior executives subsequently convicted of fraud in the United States. Customers who had left balances on those platforms became unsecured creditors in insolvency proceedings that took years to work through, with recoveries varying considerably by platform and by claim type. The lesson is narrow and worth stating precisely: a platform balance is an IOU, and the quality of that IOU depends on the financial condition, internal controls, and regulatory supervision of the company issuing it, none of which a customer can fully observe from the outside. Deposit-protection schemes that cover bank and brokerage customers generally do not extend to crypto held on trading platforms, though the position differs by jurisdiction and by product and has been changing as rules develop.
Sensible security hygiene is mostly unglamorous. Keep a recovery phrase offline and physically secure rather than photographed or saved in a cloud service; never type it into a website or share it with anyone claiming to be support, because no legitimate service ever needs it; treat unsolicited messages, links, and urgent requests as hostile by default; use app-based rather than SMS-based two-factor authentication on platform accounts; and send a small test transfer before moving a large balance. It is also worth considering whether the people who would need to find your holdings after you could realistically do so. This article is general education, not financial advice, and it does not recommend any exchange, wallet, or product. Crypto is a high-risk asset class: prices can fall sharply, platforms can and do fail, and self-custody mistakes are typically irreversible, so a total loss is a real possibility. Rules and protections differ by jurisdiction and change over time, so verify current details from official sources and a qualified professional before acting.
This article is educational and general in nature. It isn’t personalized investment, tax, or legal advice — always weigh your own circumstances, or talk to a licensed professional, before making financial decisions.