Part of the CustodyStress archive of observed Bitcoin custody incidents
CS-00615
Documentation absent — Coincheck (2018)
IndeterminateCase description
Coincheck had stored all NEM in a single hot wallet with no multi-signature protection, contrary to industry standards. The exchange had not disclosed this practice to customers. NEM holders had no indication their assets were held in a single unprotected address. The post-hack disclosure revealed a complete absence of documented custody procedures for customer assets.
Custody context
| Stress condition | Documentation absent |
| Custody system | Exchange custody |
| Outcome | Indeterminate |
| Documentation | Unknown |
| Year observed | 2018 |
| Country | Japan |
Structural dependencies observed
What this illustrates
Nobody had written down how to get back in. That knowledge existed only in the owner's head. It's not clear whether anyone ever regained access.
Outcome interpretation
Not enough information is available to determine the outcome.
Source
Publicly Reported
Evidence type
News article
Evidence link
Related cases involving documentation absent
This archive documents observed custody survivability failures. It does not attempt to document all Bitcoin losses or security incidents.
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Framework references
Where Bitcoin Custody Intersects Legal and Fiduciary Authority
Where custody creates gaps in estate planning, fiduciary duty, and professional responsibility.
Professional Scope Boundary Matrix
What each professional or product covers, what they do not, and where gaps form between them.
The Independent Assessment Layer in Bitcoin Custody
How independent diagnostic layers emerge when multiple parties depend on shared infrastructure.