Hot-wallet keys were copied in 2011 and theft continued undetected for years against commingled customer assets. The exchange's 2011 on-chain solvency demonstration proved control of coins that were already being drained.
Approximately 850,000 BTC missing at bankruptcy; analysts attribute roughly 650,000 to progressive theft.
A point-in-time proof that coins exist says nothing about who controls them next week. This is the founding case for why attestation is not safekeeping.
These are the custody configurations structurally exposed to this kind of event. It describes the failure class, not any individual holder.
Whether your own arrangement sits in one of those groups is the question our Custody Independence Standard is designed to answer, and the four questions in Is your custody setup actually safe? walk through it.
WizSec investigation, bankruptcy filings
Figures are as reported by the named sources. Proof of Custody has not independently reproduced the underlying analysis.
Proof of Custody, "Mt. Gox" incident record, proofofcustody.io/incidents/mt-gox-2014Hot-wallet keys were copied in 2011 and theft continued undetected for years against commingled customer assets. The exchange's 2011 on-chain solvency demonstration proved control of coins that were already being drained. Reported loss: ~650,000 to 850,000 BTC.
A point-in-time proof that coins exist says nothing about who controls them next week. This is the founding case for why attestation is not safekeeping.
This class of failure could reach: bitcoin left on an exchange. It describes the failure class rather than any individual holder.