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ExtoWallet Card

🔍 Last analysed 27th April 2022 . No source for current release found

Without public source of the reviewed release available, this product cannot be verified!

As part of our Methodology, we ask:

Is the source code publicly available?

If the answer is "no", we mark it as "No source for current release found".

A wallet that claims to not give the provider the means to steal the users’ funds might actually be lying. In the spirit of “Don’t trust - verify!” you don’t want to take the provider at his word, but trust that people hunting for fame and bug bounties could actually find flaws and back-doors in the wallet so the provider doesn’t dare to put these in.

Back-doors and flaws are frequently found in closed source products but some remain hidden for years. And even in open source security software there might be catastrophic flaws undiscovered for years.

An evil wallet provider would certainly prefer not to publish the code, as hiding it makes audits orders of magnitude harder.

For your security, you thus want the code to be available for review.

If the wallet provider doesn’t share up to date code, our analysis stops there as the wallet could steal your funds at any time, and there is no protection except the provider’s word.

“Up to date” strictly means that any instance of the product being updated without the source code being updated counts as closed source. This puts the burden on the provider to always first release the source code before releasing the product’s update. This paragraph is a clarification to our rules following a little poll.

We are not concerned about the license as long as it allows us to perform our analysis. For a security audit, it is not necessary that the provider allows others to use their code for a competing wallet. You should still prefer actual open source licenses as a competing wallet won’t use the code without giving it careful scrutiny.

The product cannot be independently verified. If the provider puts your funds at risk on purpose or by accident, you will probably not know about the issue before people start losing money. If the provider is more criminally inclined he might have collected all the backups of all the wallets, ready to be emptied at the press of a button. The product might have a formidable track record but out of distress or change in management turns out to be evil from some point on, with nobody outside ever knowing before it is too late.

Help spread awareness for build reproducibility

Please help us spread the word discussing transparency with ExtoWallet Card  via their Twitter!

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.

The Analysis 

Product Description

From their page:

  • Secure means of creating and storing your private crypto keys
  • On-card fingerprint recognition and Pin input
  • Navigation touch wheel
  • E-ink display
  • Secure Bluetooth connectivity
  • Built-in NFC and USB connecvity
  • Rechargerable battery
  • USB charging cradle and cable

They also claim that the smart card also has an EMV chip and ‘easy’ multi-signature cosigning through the device and a mobile phone:

Multi-signature Crypto Wallets are known to be the safest way to keep custody of crypto-currencies. But they have been difficult to set up and therefore not used other than by expert users or institutional custodians and exchanges. ExtoWallet is the first crypto wallet that enables easy to use cosigning, with one key on the ExtoCard and a second on your iOS or Android smartphone.

Both devices are required to cosign all transactions using multi-sig features native to the crypto asset, leading to unparalleled security. (Bitcoin Cash, ETH & ERC20 cosigning coming soon).

The ExtoCard utilizes on-card fingerprint recognition or pin and the ExtoWallet App utilizes iOS/Android biometric access or pin for multi-factor authentication.

Mnemonic Recovery is Possible

The display and touch navigation allow secure on card recovery of wallets using 12 keywords.

Furthermore, they also claim that the ExtoWallet App is Open Source. However, we were not able to find a link from their site to a repository. A search on Google Play also did not yield the described app. We were able to find the iPhone app ExtoWallet No Source! Defunct! . They tried to launch a Kickstarter campaign for the Android app, but there was no word on what transpired after.