Part of the CustodyStress archive of observed Bitcoin custody incidents
CS-00343
Blockchain.info Hosted Wallet Recovery Attempt: Partial Password, No Seed Backup
Indeterminate
Custodial platform became inaccessible — whether funds were recovered is not documented.
Case description
In October 2017, a BitcoinTalk user identified as Parodium reported being locked out of a blockchain.info wallet created years earlier. The user retained email access and wallet identification details but could recall only approximately 60% of the account password and possessed no backup of the mnemonic seed phrase, private key, or encrypted wallet file. Blockchain.
info, operating as a custodial hosted wallet provider, stated explicitly that they could not assist with password recovery due to their claimed architectural design: the service did not retain access to user passwords or wallet data. This was presented as a security feature—the provider's inability to reset credentials—but it became an absolute barrier when the user needed recovery assistance. The user first engaged walletrecoveryservices, a professional password recovery firm, but this engagement produced no result. Faced with this constraint, Parodium posted to BitcoinTalk offering a 0.
5 BTC bounty for detailed instructions on using the btcrecover tool on Windows 10, specifically requesting guidance on retrieving the wallet.aes.json encrypted payload file from blockchain.info and configuring btcrecover with suspected password permutations.
A secondary bounty of 0.75 BTC was offered to anyone with sufficient computational resources willing to attempt the crack directly, contingent on demonstrating trustworthiness and equipment capability. Community responses ranged from suggestions to contact blockchain.info support (which proved futile) to memory-reconstruction techniques.
User SM23031997 offered assistance with btcrecover configuration but acknowledged previous password-cracking attempts had failed due to hardware limitations. By late November 2017, HCP provided the most detailed technical guidance, suggesting the user attempt direct API queries to blockchain.info for the encrypted wallet file and potentially request the payload after identity verification. The thread remained active through at least November 20, 2017, with the user periodically bumping it for assistance.
No resolution was documented in the available record. The case exemplifies the custodial dependency trap: a user's access to funds was entirely contingent on password recovery from a service provider that, by design and policy, provided no recovery pathway.
Custody context
| Stress condition | Vendor lockout |
| Custody system | Exchange custody |
| Outcome | Indeterminate |
| Documentation | Partial |
| Year observed | 2017 |
Structural dependencies observed
What this illustrates
The wallet needed a passphrase that nobody could produce. Exchange custody eliminates key management complexity but replaces it with platform dependency. The holder does not control private keys — access runs entirely through the platform. Custodial arrangements shift the locus of control from the holder to the institution. When the institution becomes unavailable — through insolvency, regulatory action, or policy change — so does access. There were some notes, but not enough to actually complete the recovery. Partial documentation creates a false sense of preparedness — enough detail to indicate a path exists, but not enough to follow it through. An indeterminate outcome reflects the limits of available information. Whether anyone eventually gained access is not documented in the sources reviewed.
Why this matters
Why custodial Bitcoin fails differently than self-custody
Vendor lockout cases follow a pattern that is structurally different from all other stress conditions in the archive. In self-custody failures, the problem is credentials — missing keys, forgotten passphrases, undiscovered backups. In vendor lockout, the credentials are often intact. The problem is that the institution that was supposed to honor them is no longer accessible.
Exchange custody transfers the custody problem from the holder to the institution. The holder no longer needs to manage seed phrases, maintain hardware, or understand cryptographic concepts. They need only to maintain their account. This simplicity has a cost: the holder no longer controls the private keys. Access depends entirely on the continued operational, financial, and regulatory health of the exchange.
Cases in this archive show that exchange failures cluster around specific event types: bankruptcy and insolvency, regulatory seizure, geographic sanctions, and account-level access failures (lost 2FA, forgotten email credentials). Each event type has a different recovery path and a different timeline. Bankruptcy proceedings typically take 6-24 months and produce partial recovery. Regulatory seizure timelines depend on legal process. Account access failures may be resolvable through platform support or may not.
The distinguishing feature of vendor lockout cases is that recovery — when it occurs — happens through processes the holder did not design and cannot control. They become claimants in a process rather than holders of an asset.
How this category of failure is typically preventable
The primary protection against vendor lockout is not using a vendor for custody beyond what is needed operationally. Holdings intended to be stored long-term are most exposed to institutional risk. Exchange custody is well-suited for active trading and conversion; it is poorly suited for long-term storage of significant value. Moving Bitcoin off exchange into self-custody eliminates platform dependency at the cost of taking on personal custody responsibility.
Read more: Bitcoin Exchange Custody Risks →
Frequently asked questions
What happens to Bitcoin if the exchange goes bankrupt?
Bankruptcy freezes customer assets during proceedings. Account holders typically cannot withdraw during this period. Depending on the jurisdiction, exchange custody, and bankruptcy structure, customers may recover some or all of their Bitcoin through the bankruptcy process — but this takes months to years, requires filing claims, and frequently results in partial recovery. Cases where the exchange operated with insufficient reserves produce the worst outcomes.
Is Bitcoin on an exchange safe?
Exchange-held Bitcoin carries platform dependency risk that self-custody does not. The exchange controls the private keys, not the holder. Platform insolvency, regulatory action, account freezes, or technical failures can all restrict access. The phrase "not your keys, not your coins" reflects this: without controlling the private keys, the holder depends entirely on the continued operation of the exchange.
Can an exchange freeze or block access to Bitcoin?
Yes. Exchanges can restrict access due to regulatory compliance requirements, suspicious activity flags, identity verification failures, sanctions compliance, court orders, or their own technical or financial problems. Self-custody Bitcoin cannot be frozen by a third party — it can only be moved by whoever holds the private keys. Exchange custody eliminates this property.
Most structurally similar case
David Vu's Blockchain.info Wallet: Trapped With 2 BTC, Secondary Password Forgotten
Vendor lockout
·
Exchange custody
· 2017
Indeterminate
Related cases
Structural patterns in this case
This archive documents observed custody survivability failures. It does not attempt to document all Bitcoin losses or security incidents.
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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.
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