Foundations4 min read

Custody and Keys

Whoever controls the private key controls the asset. There is no institution positioned to reverse a transfer, restore access or adjudicate a dispute.

MadStockAlerts Research · Updated August 29, 2026

What to take away

  • A private key authorises transfers; possession of it is effectively ownership.
  • Self-custody means no recovery mechanism if the key is lost.
  • Custodial holding replaces key risk with counterparty risk.
  • Transfers are final, and an address typed incorrectly is generally unrecoverable.
  • The protections described elsewhere in this library largely do not apply here.

MAD Academy Training Video · 0:45

The Key Is the Asset

Ownership is possession of a private key, which makes self-custody genuinely final in both directions.

This lesson is part of a Stock Alerts + Tools plan.

See the library

The two arrangements

Self-custodyCustodial
Who holds the keyYouThe platform
Primary riskLosing the key, or having it stolenThe platform failing or misusing assets
Recovery if access is lostNone, beyond your own backupAn account recovery process
Reversal of an erroneous transferNoneOccasionally possible if it stayed internal
Exposure in an insolvencyNone to a platformYou are a creditor, and the outcome depends on the law

The trade-off is genuine and there is no arrangement that avoids both risks. Self-custody removes counterparty exposure and places the entire operational burden on the holder; custodial holding does the reverse.

There is no arrangement without a risk
A process existsNone
A platformYou
Not availableSelf-custody has no recovery mechanism by design
CustodialAccount recovery exists, and you are a creditor if the platform fails
Self-custodyNo counterparty, and no recovery. A lost key is a lost asset
Not available
Who holds the key
Self-custody removes counterparty exposure and places the entire operational burden on the holder. Custodial holding does the reverse. Both risks are real and neither arrangement avoids both.

What finality means in practice

A transfer confirmed on a public chain is not reversible by anyone. There is no institution with the authority to unwind it, and no process equivalent to a chargeback or a payment recall.

  • An address entered incorrectly sends the asset to that address, which may be controlled by nobody.
  • A transfer sent on the wrong network can be unrecoverable even where the address looks valid.
  • A transfer induced by fraud is as final as any other.
  • Support at a platform can help with internal balances and cannot alter a confirmed on-chain transaction.

This is the single largest practical difference from a brokerage account, and it is the reason the fraud material in this library applies here with the recovery routes removed.

How keys are held

MethodCharacteristic
Hardware deviceThe key never leaves the device; transactions are signed on it
Software walletKey held on a general-purpose device, and exposed to its compromises
Recovery phrase on paper or metalThe key material in human-readable form; possession is control
Multi-signatureSeveral keys required to authorise, which removes any single point of failure
Custodial accountNo key held by the user at all

The third row is the most consequential and the most mishandled. A recovery phrase is the asset. Anyone who reads it can take everything, and any request to enter one anywhere is a request for the asset itself.

Which protections apply

  • Deposit insurance does not apply. These are not bank deposits.
  • Securities investor protection applies to securities held at a registered broker-dealer, which most crypto platforms are not.
  • Private insurance carried by a platform is a commercial policy with its own terms and limits, and it is not a protection scheme.
  • Where a platform holds assets in its own name rather than segregating them, holders may be unsecured creditors in an insolvency.

The last item has been tested. Insolvencies in the sector have turned account holders into unsecured creditors, with recoveries determined by bankruptcy proceedings years later, which is a materially different position from holding securities at a broker.

The operational failures that actually occur

Losses in self-custody are dominated by a small number of failure modes, none of which involve the cryptography being broken.

  • A recovery phrase lost, destroyed, or stored where it could not be found later.
  • A recovery phrase entered into a fraudulent site or application that requested it.
  • A device compromised by software that had access to the key material.
  • A transfer sent to a wrong or malformed address, or on the wrong network.
  • A single point of failure: one phrase, one location, one person who knew where it was.

The second item is the most common current form and it is entirely social. No legitimate service, wallet or support process ever needs a recovery phrase, and any request for one is a request for the assets.

The last item is also an estate question. Assets in self-custody with no documented recovery path are unrecoverable by anyone else, which is a consideration with no equivalent in a brokerage account.

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