Green: Bitcoin Wallet

less than 1 minute read

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Wallet Logo

This app was first launched on 1st January 2015 and currently has more than 50000 downloads, a 4.3 stars rating from 481 users and the latest APK (version 3.3.4) was from 10th February 2020.

Our analysis was done on 17th February 2020 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:

Older reviews

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Please follow Green: Bitcoin Wallet and thank them for being verifiable via their Twitter!

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

Here we test if version 3.3.4 is verifiable. See older reviews for more.

With this script our results are:

Results for
appId: com.greenaddress.greenbits_android_wallet
apkVersionName: "3.3.4"
apkHash: f88686a2e41718b82ba8d2f5ff7eb8d0ada044d29711e75f0128104bbee40baf

Diff:

Files /tmp/fromPlay_com.greenaddress.greenbits_android_wallet_22000334/apktool.yml and /tmp/fromBuild_com.greenaddress.greenbits_android_wallet_22000334/apktool.yml differ
Only in /tmp/fromPlay_com.greenaddress.greenbits_android_wallet_22000334/original/META-INF: GREENADD.RSA
Only in /tmp/fromPlay_com.greenaddress.greenbits_android_wallet_22000334/original/META-INF: GREENADD.SF
Files /tmp/fromPlay_com.greenaddress.greenbits_android_wallet_22000334/original/META-INF/MANIFEST.MF and /tmp/fromBuild_com.greenaddress.greenbits_android_wallet_22000334/original/META-INF/MANIFEST.MF differ

And that diff looks exactly as it should look. Our verdict for version 3.3.4: This app is verifiable.

Verdict Explained

Verifiable: The provided Open Source Code matches the app released on Google Play

The app can be independently verified. If the provider puts your funds at risk on purpose or by accident, security researchers can see this if they care to look. It also means that inside the company engineers can verify that the release manager is releasing the app based on code known to all engineers on the team. A scammer would have to work under the potential eyes of security researchers. He would have to take more effort in hiding any exploit.

"Verifiable" does not mean "verified". There is good reason to believe that security researchers as of today would not detect very blatant backdoors in the open source code before it gets exploited, much less if the attacker takes moderate efforts to hide it.