Part of the CustodyStress archive of observed Bitcoin custody incidents
Bitcoin Custody Structural Dependencies
Structural dependencies documented across observed Bitcoin custody failures — the components and conditions that custody systems rely on, and where that reliance produced access failures.
A structural dependency is any component or condition a custody system relies on to function — a passphrase stored in memory, an institution that must cooperate, a person who must act, a document that must be located. Dependencies are not inherently failures. They become failure surfaces when the component they rely on becomes unavailable under stress.
The archive classifies structural dependencies per case from available documentation. Each dependency category below links to the cases where that dependency contributed to an access failure.
These dependency pages are distinct from the archive's scenario pages. Scenarios describe the stress condition that triggered a failure. Dependencies describe the structural property that made a custody system vulnerable to that stress.
Dependency Overview
Single-Person Knowledge
The custody arrangement was understood only by one person — holder, operator, or key manager. No second person had sufficient knowledge to execute recovery independently.
Documented cases 596
Common stress condition Passphrase unavailable
Observed outcomes 80% of determinate cases resulted in blocked access
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Passphrase Dependency
Recovery required a BIP39 passphrase, wallet encryption passphrase, or PIN stored only in the holder's memory or in a location that became inaccessible.
Documented cases 414
Common stress condition Passphrase unavailable
Observed outcomes 68% of determinate cases resulted in blocked access
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Undocumented Recovery Procedure
No written procedure existed for how recovery would be executed. The holder understood the arrangement; no record existed to guide anyone else.
Documented cases 546
Common stress condition Passphrase unavailable
Observed outcomes 73% of determinate cases resulted in blocked access
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Institutional Cooperation Required
Completing recovery required active cooperation from an exchange, custodial platform, or third-party service — cooperation that became unavailable.
Documented cases 198
Common stress condition Vendor lockout
Observed outcomes 60% of determinate cases resulted in blocked access
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Device-Dependent Access
Access to the wallet depended on a specific physical device, with no device-independent recovery path documented.
Documented cases 549
Common stress condition Passphrase unavailable
Observed outcomes 74% of determinate cases resulted in blocked access
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Shared Service Dependency
Multiple access or recovery paths converged on the same platform or service, creating a single point of failure beneath apparent redundancy.
Documented cases 170
Common stress condition Vendor lockout
Observed outcomes 57% of determinate cases resulted in blocked access
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Legal Authority Required
Completing recovery required formal legal standing — probate, power of attorney, or court authorization — that was not in place or could not be established.
Documented cases 59
Common stress condition Vendor lockout
Observed outcomes 58% of determinate cases resulted in blocked access
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Geographic Access Constraint
Recovery materials, devices, or institutional access required geographic presence that was unavailable due to relocation, displacement, or jurisdictional barriers.
Documented cases 36
Common stress condition Coercion
Observed outcomes 81% of determinate cases resulted in blocked access
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Time-Sensitive Sequencing
Recovery required steps to be performed in sequence within a limited time window — a window that closed before recovery could be completed.
Documented cases 31
Common stress condition Vendor lockout
Observed outcomes 36% of determinate cases resulted in blocked access
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Recovery Materials Colocated
Multiple components of the custody system — seed phrase, passphrase, device, signing keys, or backup copies — were stored at the same physical location. Cases formerly classified as key colocation are included here.
Documented cases 17
Common stress condition Coercion
Observed outcomes 69% of determinate cases resulted in blocked access
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Dependency Comparison Across the Archive
Blocked % calculated from determinate cases only. A case may involve more than one dependency.
Cases may involve multiple dependencies. Counts reflect cases where each dependency was documented as present.
What Dependencies Reveal
Dependencies are structural, not incidental
Most Bitcoin custody failures are not caused by lost keys. They are caused by reliance on something that became unavailable. The key was held by one person who died. The passphrase existed only in memory that faded. The institution had to cooperate and went bankrupt. The device held the only copy and was destroyed. Dependency classification surfaces the structural layer beneath the incident — the design property that made the system vulnerable before the stress event occurred.
The same dependency appears across different scenarios
Single-person knowledge fails under owner death, owner incapacity, coercion, and cognitive failure alike. Passphrase dependency fails under device loss, cognitive failure, and inheritance. Institutional cooperation dependency fails under vendor lockout and legal authority constraint. Dependency classification reveals which structural properties produce failures across multiple scenario types — the custody properties that are broadly fragile, not just fragile in one condition.
Multiple dependencies compound failure probability
A case may involve several dependencies simultaneously. Single-person knowledge combined with undocumented procedure is the most common pairing in the archive — the holder both held sole knowledge and left no written procedure to substitute for it. Where dependencies compound, the blocked outcome rate increases substantially. The archive documents cases as they occurred, not as they were designed to function.
Observations from the archive
Single-Person Knowledge is the most frequently observed structural dependency in the archive, appearing in 596 documented cases across all custody types and stress conditions.
Geographic Access Constraint has the highest blocked rate among dependencies with sufficient cases to measure — 81% of determinate cases resulted in no documented recovery path.
Dependency classification reflects structural properties documented in individual cases. A case is tagged with a dependency when that dependency contributed to the access failure under documented conditions. The archive does not claim these are the only dependencies present — only those identifiable from available sources.
Outcome terms
Survived
Access remained possible under the reported conditions.
Constrained
Access remained possible, but only with delay, dependence, or significant difficulty.
Blocked
Access was not possible under the reported conditions.
Indeterminate
There was not enough information to determine the outcome.
Assessment terms
Survivability
The degree to which a custody system maintains the possibility of authorized recovery under stress.
This archive documents cases where a legitimate owner, heir, or authorized party encountered barriers accessing or recovering Bitcoin due to a failure in the custody arrangement. The central question for inclusion is: did the custody structure fail a legitimate access or recovery attempt?
Inclusion requirements
A case must satisfy all three of the following to be included:
- Legitimate access attempt. The person attempting to access or recover the Bitcoin was the owner, a designated heir, an executor, a legal authority, or another party with a legitimate claim — not a thief, attacker, or unauthorized third party.
- Custody structure failure. The failure was caused by a property of the custody arrangement — missing credentials, structural dependencies, documentation gaps, knowledge concentration, legal barriers, or institutional constraints — not market conditions, individual-level fraud or theft, or protocol-level issues. Platform-level failures that block legitimate user access are in scope regardless of their cause.
- Documentable outcome or access constraint. The case must have a stated or inferable outcome: access blocked, access constrained, access delayed, or access eventually achieved through a recovery path. Cases with entirely unknown outcomes are included only where the structural failure is documented and the constraint is unambiguous.
In scope
- Owner death or incapacity — Bitcoin held in self-custody that becomes inaccessible to heirs or designated parties because credentials, documentation, or operational knowledge were not transferred
- Passphrase loss — BIP39 passphrase forgotten or unavailable, blocking access to a funded wallet even where the seed phrase is present
- Seed phrase or wallet backup unavailable — no independent recovery path existed or the backup was destroyed, lost, or never created
- Device loss without independent backup — hardware wallet, phone, or computer lost or destroyed with no recovery path outside the device
- Documentation absent or ambiguous — heirs or executors cannot determine that Bitcoin exists, which wallet holds it, or how to access it
- Knowledge concentration — only one person knew the procedure, passphrase, or access method; that person is dead, incapacitated, or unreachable
- Multisig quorum failure — a threshold signature arrangement cannot be completed because signers are unavailable, uncooperative, incapacitated, or have lost their keys
- Legal authority / access mismatch — a court order, probate ruling, or power of attorney establishes legal entitlement but provides no technical path to access
- Institutional custody barrier — exchange or platform hacks, insolvency, regulatory seizure, or operational failure that caused a access constraint or failure for legitimate users, whether temporary, prolonged, or permanent. The failure of the custodian to remain available or solvent is itself the in-scope event.
- Forced relocation or geographic constraint — physical access to a device or location required for recovery is blocked by displacement, border restrictions, or political circumstances
- Coercion — the holder was compelled under threat to transfer Bitcoin or disclose credentials during an access event
- Hidden asset discovery — heirs or executors locate a wallet or account but cannot access it due to missing credentials or operational knowledge
Out of scope
- Market losses, investment losses, yield scheme losses, or Ponzi scheme losses
- Hacks or theft targeting an individual's personal security (phishing, SIM swap, social engineering, malware) where the custody architecture itself did not fail
- Unauthorized transfers where the holder's custody system was not the cause of the failure
- Ordinary transaction mistakes — wrong-address sends, fee errors, mistaken amounts
- Protocol-level failures — cryptographic vulnerabilities, consensus bugs, firmware integrity failures
- Deliberate burns or tribute burns
- Cases where the stated loss is unverifiable and no structural custody failure is described
Source and verification
Cases are drawn from public sources including forum posts, news reporting, court documents, academic research, and direct submissions. Each case is reviewed against the inclusion criteria above before publication. Source material is retained and available on request for documented cases.
The archive is observational and descriptive. It does not attempt to document all Bitcoin custody failures — only those meeting the criteria above with sufficient documentation to describe the structural failure and its outcome.