Forgotten Blockchain.info Password: Client-Side Encryption Locks €100 Bitcoin Permanently
BlockedWallet passphrase could not be recalled or recovered — access was permanently blocked.
On September 17, 2015, a Blockchain.info user with the forum username Seporstia posted requesting help recovering access to a hosted wallet after forgetting the password. The account held approximately €100 worth of Bitcoin (roughly $110 USD at 2015 exchange rates). Seporstia initially offered to pay half the recovery value to anyone able to help.
Blockchain.info operated on a client-side encryption model: the platform never stored user passwords on its servers, meaning even Blockchain.info staff could not retrieve or reset lost credentials. This design choice prioritized security over account recovery—a trade-off clearly stated in the platform's own warning: 'Forgotten passwords are UNRECOVERABLE and will result in LOSS of ALL of your bitcoins.'
Seporstia pursued multiple recovery avenues. First, the user attempted to use Blockchain.info's wallet recovery feature, which requires the mnemonic seed phrase—information the user could not reliably recall. Second, Seporstia located a wallet backup file (wallet.aes.json) stored on Dropbox. A community member provided detailed technical guidance on decrypting the JSON file using publicly available tools and decryption guides, but the backup file was encrypted using the same password as the wallet itself, creating a circular dependency. Without the original password, decryption was impossible.
Community response was substantial and technically sound. Multiple experienced members, including Bitcoin Core contributor achow101, provided accurate explanations of Blockchain.info's custody model and the specific constraints it imposed. The consensus was unambiguous: without either the mnemonic seed phrase or successful password recovery, the funds were permanently inaccessible.
By the thread's final post on September 17, 2015 at 09:21 AM, no recovery path had succeeded. The account remained locked, and no documented solution emerged from the discussion.
| Stress condition | Passphrase unavailable |
| Custody system | Exchange custody |
| Outcome | Blocked |
| Documentation | Present and interpretable |
| Year observed | 2015 |
| Country | unknown |
Why passphrases fail years after they are set
The failure mode documented consistently across observed cases is temporal: the passphrase is set with confidence, not used for an extended period, and then cannot be reproduced exactly when needed. A single character difference — different capitalization, an added space, a slightly different special character — produces a different wallet with a zero balance. The holder may be certain they remember the passphrase while being unable to produce the exact string that was originally set.
What makes this particularly difficult is that there is no signal at the moment of failure. A wrong passphrase does not produce an error message. It opens an empty wallet. The holder sees a zero balance and typically concludes the passphrase was wrong — but without knowing which part was wrong, or by how much.
Professional passphrase recovery services can attempt permutations when the holder has partial information: they remember the general structure, typical patterns they use for passwords, the approximate length, or that it included a specific word. Recovery from total non-recollection is not feasible.
The preventive action is to store a passphrase record — not with the seed phrase, which would defeat its security purpose, but in a separate secure location accessible to the holder and potentially a designated recovery person. A passphrase that exists only in memory has a time horizon: it will eventually be forgotten, and the timing is unpredictable.
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