DropBit: Bitcoin Wallet

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Wallet Logo

This app was first launched on 1st August 2018 and currently has more than 10000 downloads, a 3.2 stars rating from 148 users and the latest APK (version 3.2.7) was from 28th January 2020 and is newer than the below reviewed version of the app.

Our analysis was done on 24th November 2019 based on data found in their Playstore description and their website and their source repository. We discuss the issue with verification with the provider here.

We found these ways of contacting the developers:

Disclaimer

The following Analysis is not a full code review! We plan to make code reviews available in the future but even then it will never be a stamp of approval but rather a list of incidents and bad coding practice. We cannot find and tell you all the dark secrets the wallet providers might have.

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.

The Analysis

This wallet does not claim to be non-custodial - in fact it is custodial for lightning but lines like this in their FAQ sound like it is non-custodial for normal Bitcoin:

I lost access to my wallet, and did not write down my Recovery Words. Can I get my wallet back?
If you did not import your DropBit wallet on any other device and you did not save a copy of your recovery words, you have lost access to your wallet. This is why it is critical to write down and store safely your recovery words.

On the website they also link to their GitHub account and from there we found “dropbit-android” to be the most promising sounding repository.

The application ID is correct but the version tells me there will be an issue with building this app:

Their build.gradle is full with System.getenv() statements which means to compile the app, these values need to be provided on the build system and are not part of the project.

For the purpose of our verification it would probably be acceptable to have some “secrets” be different in the diff, provided they are not obfuscated causing a diff all over the place.

Looking at their tags in the search for the right version 3.2.0 we are not lucky neither:

$ git tag
1.4.1
1.4.4
1.4.5
1.4.6
1.5.0
1.5.1
1.6.0
1.6.1
1.7.0
2.0.0
2.1.0
2.2.0
2.3.0
2.3.1
2.3.2
2.3.4
3.0
3.0.1
3.0.2
3.1.0
3.1.1

Given their last commit is Merge branch ‘3.1.1RC’ into ‘master’ we have to assume that this wallet currently can not be verified.

Verdict Explained

Not verifiable: The provided Open Source Code could not be verified to match the app released on Google Play

This verdict means that the provider did share some source code but that we could not verify that this source code matches the released app. This might be due to the source being released later than the app or due to the provided instructions on how to compile the app not being sufficient or due to the provider excluding parts from the public source code. In any case, the result is a discrepancy between the app we can create and the app we can find on GooglePlay and any discrepancy might leak your backup to the server on purpose or by accident.

As we cannot verify that the source provided is the source the app was compiled from, this category is only slightly better than closed source but for now we have hope projects come around and fix verifiability issues.

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.