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Opendime

🔍 Last analysed 31st October 2022 . Plain Keys when spending
1st April 2016

This product eventually requires sharing private key material.

As part of our Methodology, we ask:

Does the device hide your keys from other devices at all time?

If the answer is "no", we mark it as "Plain Keys when spending".

These devices keep the user’s private key sealed until the seal is broken or removed.

In order for a transfer to commence, the private keys have to be brought onto a different system that might not be secure.

There are many viruses known to look for Bitcoin private keys in memory or hard drives.

While this aspect should not leave room for major exit scams, the handling of such devices is delicate and prone to loss of funds to hackers.

To redeem your funds safely, create your transaction on an offline machine and verify the signed transaction on a different machine before broadcasting it.

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Do your own research!

Try out searching for "lost bitcoins", "stole my money" or "scammers" together with the wallet's name, even if you think the wallet is generally trustworthy. For all the bigger wallets you will find accusations. Make sure you understand why they were made and if you are comfortable with the provider's reaction.

If you find something we should include, you can create an issue or edit this analysis yourself and create a merge request for your changes.

What is a bearer token?

Bearer tokens are meant to be passed on from one user to another similar to cash or a banking check. Unlike hardware wallets, this comes with an enormous "supply chain" risk if the token gets handed from user to user anonymously - all bearer past and present have plausible deniability if the funds move. We used to categorize bearer tokens as hardware wallets, but decided that they deserved an altogether different category. Generally, bearer tokens require these attributes:

  • Secure initial setup
  • Tamper evidence
  • Balance check without revealing private keys
  • Small size
  • Low unit price
and either of these applies:
  • Somebody has a backup and needs to be trusted.
  • Nobody has a backup and funds are destroyed if the token is lost or damaged.

The Analysis 

Updated Verdict

  1. The user plugs the device via USB and generates entropy by saving a random file on the device.
  2. To have access to the private key, the user must poke a hole through a seal on the device.
  3. The device’s private keys are then displayed via a text file, where it can be imported to another wallet.

Verdict

To spend the funds, the private keys need to get exposed to potentially insecure systems. A virus on that system could empty the wallet the second the device gets plugged into the USB port.

(ml, fj, lw, dg)