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Muun - Bitcoin and Lightning Wallet

latest release: 46.7 last analysed  6th April 2021 Not reproducible from source provided  
4.6 ★★★★★
261 ratings
25th April 2017

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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.

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 

Update 2021-04-06: The provider announced that the app is reproducible now. We will have to check that …

So they now have build instructions for reproducible builds. Promising! Let’s see how that goes …

$ sha256sum fromGoogle45.2.apk # just for the record, the apk hash:
292776e270739d37b9307465cbddfc11068813078d9633035d74ae67f322a3b2  fromGoogle45.2.apk
$ cd /tmp/
$ git clone https://github.com/muun/apollo
$ cd apollo/
$ git checkout v45.2
$ mkdir -p apk
$ docker build -f android/Dockerfile -o apk .
62 actionable tasks: 60 executed, 1 from cache, 1 up-to-date
Removing intermediate container 9812d21025c9
 ---> d997f192afe8
Step 24/26 : FROM scratch
Step 25/26 : COPY --from=build /src/android/apolloui/build/outputs/apk/prod/release/apolloui-prod-release-unsigned.apk apolloui-prod-release-unsigned.apk
 ---> 5b8f679ee607
Step 26/26 : COPY --from=build /src/android/apolloui/build/outputs/mapping/prodRelease/mapping.txt mapping.txt
 ---> ad2ddc6ce00f
Successfully built ad2ddc6ce00f
$ ls *.apk
$ ls apk/

so the apk did not end up where it’s supposed to end up but it should be part of the docker image now:

$ docker images
REPOSITORY                                                 TAG                    IMAGE ID            CREATED             SIZE
<none>                                                     <none>                 ad2ddc6ce00f        31 minutes ago      59.1MB
<none>                                                     <none>                 d997f192afe8        31 minutes ago      10.3GB

with some poking around with interactive runs, I found this works:

$ docker run --rm --volume $(pwd)/apk:/apk d997f192afe8 cp ./android/apolloui/build/outputs/apk/prod/release/apolloui-prod-release-unsigned.apk /apk/
$ ls apk/
$ apktool d -o fromBuild apk/apolloui-prod-release-unsigned.apk 
$ apktool d -o fromGoogle fromGoogle45.2.apk 
$ diff --brief --recursive from{Google,Build}
Files fromGoogle/apktool.yml and fromBuild/apktool.yml differ
Only in fromGoogle/original/META-INF: APOLLORE.RSA
Only in fromGoogle/original/META-INF: APOLLORE.SF
Files fromGoogle/original/META-INF/MANIFEST.MF and fromBuild/original/META-INF/MANIFEST.MF differ
Files fromGoogle/res/values/strings.xml and fromBuild/res/values/strings.xml differ

so the only diff of interest is in res/values/strings.xml:

$ diff from{Google,Build}/res/values/strings.xml
<     <string name="com.crashlytics.android.build_id">79a4d6b75ce84bd6ae254b900862f3a4</string>
>     <string name="com.crashlytics.android.build_id">976f51d22fdf4feda23c0dbc83806a9f</string>

That’s almost reproducible. On a subjective level, if somebody reviewed the source code and it is fine then yes, the apk is also fine but as we only allow diffs in the signature part itself, it is too much of a diff for a reproducible verdict. The app is close but still not verifiable.


Verdict Explained

We could not verify that the provided code matches the binary!

As part of our Methodology, we ask:

Is the published binary matching the published source code? If not, we tag it Unreproducible!  

Published code doesn’t help much if it is not what the published app was built from. That is why we try to reproduce the binary. We

  1. obtain the binary from the provider
  2. compile the published source code using the published build instructions into a binary
  3. compare the two binaries
  4. we might spend some time working around issues that are easy to work around

If this fails, we might search if other revisions match or if we can deduct the source of the mismatch but generally consider it on the provider to provide the correct source code and build instructions to reproduce the build, so we usually open a ticket in their code repository.

In any case, the result is a discrepancy between the app we can create and the app we can find on the app store 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.