Resources and Reviews

Opendime Review: One Of The Most Interesting Bitcoin Hardware Wallets

Everyone knows Trezor and Ledger. These Bitcoin hardware wallets – they support several altcoins as well – took on the market with innovative products and great marketing schemes.

But there are other hardware wallets that provide exceptional functionality and features that Trezor and Ledger just don’t provide.

That is the case of Opendime, which has one of the most interesting Bitcoin hardware wallets that allow Bitcoin enthusiasts to go dark.

Opendime: Part of the Coinkite Product Suite

opendime bitcoin wallet logo

While searching for Opendime, you might come across other hardware wallets and interesting product bundles with different names. That is because CoinKite, the makers of Opendime, are also behind brilliant products like Coldcard wallets.

Here are some basic distinctions that make both Opendime devices and Coldcard Bitcoin wallets complementary:

  • Opendime works as a one-time Bitcoin hardware wallet
  • This means it can be loaded with Bitcoin once and then used to spend the amount loaded off-chain
  • It has tamper-proof mechanisms – especially well developed in v4
  • Coldcard is a multi-use Bitcoin hardware wallet much like Trezor and Ledger
  • Opendime is designed for short to medium-term use on off-chain transactions
  • Coldcard is a long-term Bitcoin hardware wallet from which you can transfer Bitcoin to your Opendime devices for immediate transactions
  • You can transfer a part of your funds into Opendime devices for safe keeping. They work just like paper wallets

Opendime Features

You can use Opendime as a stand-alone device or in combination with any other Bitcoin wallet in the market. Here are the features that make this device unique and help it cover a gap in the market:

opendime bitcoin wallet by coinkite
  • Small, portable, read only device that only works with Bitcoin
  • Looks like a USB key with an exposed circuit board on it, and it functions as a flash drive
  • There is a protective cover over the electronic components to make it resilient
  • Opendime circuits have a useful lifetime of at least 25 years
  • The device generates its own private keys once the user drags and drops a random computer file into the drive
  • Private keys are not revealed until the circuit board changes physically
  • Revealing private keys on the device to spend the Bitcoin amount in it requires a user to pop a transistor out
  • Once the private keys are revealed, the device cannot be transferred to another person securely

Opendime Off-Chain Transactions

These features allow Opendime to turn Bitcoin into cash. You can make transactions and purchases simply by passing the device with any given amount of Bitcoin, onto someone else.

The caveat is that you must trust the person you are dealing with. As long as you apply the same logic in an Opendime transaction as you do with a large cash transaction, you will understand how to be safe.

When used safely, Opendime bridges that gap between cash and Bitcoin in that it brings the cryptocurrency into the physical world.

These off-chain transactions can also contribute to solve scalability issues. Since the coins are not sent through the network, there is less throughput, allowing more Bitcoin to change hands without putting additional stress on the network.

opendime bitcoin stick
The Opendime Bitcoin wallet is the size of a usb stick

Opendime Transactions are Fee-Less

Additionally, Opendime transactions are fee-less. Apart from the initial purchase of the device, people paying with an Opendime wallet will not incur in any additional costs.

In fact, the first person that initiates the payment using this device, bears all the cost, regardless of how many times the wallet changes hands afterwards.

Drawbacks of Using Opendime Devices

Opendime devices do have a few shortcomings. Although they bridge the gap between Bitcoin’s digital-based transactions and the physical world, they are not entirely like cash.

Anyone receiving an Opendime wallet as a payment must keep the following in mind: 

  • If they want to re-use the device for a payment, the amount on the transaction must be at least the same as the amount they got when they received the original payment
  • Users will be able to add Bitcoin to the device without revealing the private keys
  • Therefore, they will be able to make larger payments than the ones they received, although they won’t be able to do so entirely off-chain – since they will have to add funds

Are Opendime Devices Secure?

Adding funds to a device that already generated private keys is safe. It is exactly the same as adding funds to any other Bitcoin address.

The device can be trusted because it generates its private keys in a decentralized manner, within the device when it is initialized. There are no traces of the private keys anywhere else except on the device itself.

Therefore, the original owner of the device will not be able to retrieve the funds once they give it to someone else nor will they be able to retrieve funds added to the device henceforth.

The only way to reveal the private keys is by removing the transistor on the circuit, which generates a clear, visible change on the device itself.

Know your Opendime Wallet

To avoid receiving a compromised device, user must understand how an Opendime wallet looks like. Here is a video of an Opendime wallet before and after its private keys are revealed:

Check this before you receive the payment.

Verify Funds

You should also plug the device into a computer and check its public address. This will allow you to verify independently how many coins the wallet has.

Plugging the device into a computer does not compromise its security in any way.

Untraceable Transactions on a Device you can Trust

Provided that you use the device responsibly and you verify everything you need independently, Opendime is probably the best way to make untraceable, off-chain transactions.

The device is trustworthy, and although it doesn’t work exactly like cash, it is the closest equivalent to it in the world of Bitcoin. It is also cheap enough if you are thinking about larger transactions, which makes it a wonderful solution.

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