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Tangem

latest release: 3.15 last analysed  10th April 2021
No source code found
3.9 ★★★★★
28th April 2018

Published:

Our last analysis is based on data found in their App Store description.
details below 

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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.

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The Analysis

This app is the companion app to an NFC card that is promoted as something like a hardware wallet but without a screen or a button it can only do what the companion app - this app - tells it to do. As such, this app is very crucial if you use these cards as your Bitcoin wallet. It has to be trustworthy and thus we consider it a Bitcoin wallet. Our mission is to look for the potential of all the users of an app lose all their funds at once which arguably cannot happen in the given configuration. The app could not collect the private keys from the cards if the cards do what they claim which cannot be publicly verified neither but even if the card does as advertised, the app could still steal a lot of funds of a lot of users if it would switch to evil-mode for all users at once. It would still require users’ interaction but the window of opportunity could easily be days to weeks before Google would remote-wipe the app or the app would get stopped from emptying wallets of unsuspecting users upon their next use.

The description on the App Store is not explaining much and neither does their website explain in clear words what this app is but I found this demo video and it clearly shows that the app is crucial for the security of your funds.

The next question would be: “Is the code public?” … but as far as I can see there is no source code available that one could inspect. That leaves us with the verdict not verifiable.

(lw)

Verdict Explained

No source code found

Without public source available, this app cannot be verified!

This verdict means that we could not find any source to compile the app from. Internally the company might do everything right but as we can't verify it, there is nothing protecting the user from an exit-scam where the provider releases an app that leaks the keys to the servers.

The app 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 app 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.