Not Your Keys, Not Your Coins

Not your keys, not your coins is the maxim that whoever controls the private keys controls the bitcoin, and that coins left with a custodian are legally and practically the custodian's to lose. Customers of Mt. Gox learned this in 2014 when roughly 850,000 bitcoin disappeared from the exchange, and FTX repeated the lesson at scale in 2022.

Why it matters

The phrase compresses a real legal distinction. Bitcoin held on an exchange is typically an IOU: the platform owns the keys, and the customer holds an unsecured claim that stands behind creditors in bankruptcy. Mt. Gox claimants waited roughly a decade for partial repayment, and FTX customers received claims valued at petition-date prices far below later market prices.

Self-custody inverts the risk. Holding one's own keys removes counterparty exposure entirely but transfers full responsibility for backups, security, and inheritance to the holder, a trade that has spawned intermediate models such as collaborative and multi-institution custody.

In the gold vs bitcoin debate

Gold has an exact parallel in the distinction between allocated metal, with specific numbered bars owned outright, and unallocated accounts that are merely claims on a dealer's inventory. Both communities converge on the same principle: possession, whether of bars or keys, is what separates ownership from a promise.