Our wallet review process
We examine wallets starting at the code level and continue all the way up to the finished app that lives on your device. Provided below is an outline of each of these steps along with security tips for you and general test results.
Custody
Self-custodial: The user holds the keys
As part of our Methodology, we ask: Is the product self-custodial?
The answer is "yes". The user has control of their own keys.
Read more
Released
20th January 2018
Application build
We encountered a build error while compiling from source code!
See the last Issue we created.
Passed 7 of 9 tests
We answered the following questions in this order:
We stopped asking questions after we encountered a failed answer.
The answer is "yes".
If the answer was "no", we would mark it as "Fake" and the following would apply:
The answer is "no". We marked it as "Fake".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "Fake" and the following would apply:
The bigger wallets often get imitated by scammers that abuse the reputation of the product by imitating its name, logo or both.
Imitating a competitor is a huge red flag and we urge you to not put any money into this product!
The answer is "yes".
If the answer was "no", we would mark it as "Not a wallet" and the following would apply:
The answer is "no". We marked it as "Not a wallet".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "Not a wallet" and the following would apply:
If it’s called “wallet” but is actually only a portfolio tracker, we don’t look any deeper, assuming it is not meant to control funds. What has no funds, can’t lose your coins. It might still leak your financial history!
If you can buy Bitcoins with this app but only into another wallet, it’s not a wallet itself.
The answer is "yes".
If the answer was "no", we would mark it as "A wallet but not for Bitcoin" and the following would apply:
The answer is "no". We marked it as "A wallet but not for Bitcoin".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "A wallet but not for Bitcoin" and the following would apply:
At this point we only look into wallets that at least also support BTC.
The answer is "yes".
If the answer was "no", we would mark it as "Can't send or receive bitcoins" and the following would apply:
The answer is "no". We marked it as "Can't send or receive bitcoins".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "Can't send or receive bitcoins" and the following would apply:
If it is for holding BTC but you can’t actually send or receive them with this product then it doesn’t function like a wallet for BTC but you might still be using it to hold your bitcoins with the intention to convert back to fiat when you “cash out”.
All products in this category are custodial and thus funds are at the mercy of the provider.
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.The answer is "yes".
If the answer was "no", we would mark it as "Custodial: The provider holds the keys" and the following would apply:
The answer is "no". We marked it as "Custodial: The provider holds the keys".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "Custodial: The provider holds the keys" and the following would apply:
A custodial service is a service where the funds are held by a third party like the provider. The custodial service can at any point steal all the funds of all the users at their discretion. Our investigations stop there.
Some services might claim their setup is super secure, that they don’t actually have access to the funds, or that the access is shared between multiple parties. For our evaluation of it being a wallet, these details are irrelevant. They might be a trustworthy Bitcoin bank and they might be a better fit for certain users than being your own bank but our investigation still stops there as we are only interested in wallets.
Products that claim to be non-custodial but feature custodial accounts without very clearly marking those as custodial are also considered “custodial” as a whole to avoid misguiding users that follow our assessment.
This verdict means that the provider might or might not publish source code and maybe it is even possible to reproduce the build from the source code but as it is custodial, the provider already has control over the funds, so it is not a wallet where you would be in exclusive control of your funds.
We have to acknowledge that a huge majority of Bitcoiners are currently using custodial Bitcoin banks. If you do, please:
- Do your own research if the provider is trust-worthy!
- Check if you know at least enough about them so you can sue them when you have to!
- Check if the provider is under a jurisdiction that will allow them to release your funds when you need them?
- Check if the provider is taking security measures proportional to the amount of funds secured? If they have a million users and don’t use cold storage, that hot wallet is a million times more valuable for hackers to attack. A million times more effort will be taken by hackers to infiltrate their security systems.
The answer is "yes".
If the answer was "no", we would mark it as "No source for current release found" and the following would apply:
The answer is "no". We marked it as "No source for current release found".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "No source for current release found" and the following would apply:
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.The answer is "yes".
If the answer was "no", we would mark it as "Failed to build from source provided!" and the following would apply:
The answer is "no". We marked it as "Failed to build from source provided!".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "Failed to build from source provided!" and the following would apply:
Published code doesn’t help much if the app fails to compile.
We try to compile the published source code using the published build instructions into a binary. If that fails, we might try to work around issues but if we consistently fail to build the app, we give it this verdict and open an issue in the issue tracker of the provider to hopefully verify their app later.
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.The answer is "yes".
If the answer was "no", we would mark it as "Not reproducible from source provided" and the following would apply:
The answer is "no". We marked it as "Not reproducible from source provided".
We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "Not reproducible from source provided" and the following would apply:
Published code doesn’t help much if it is not what the published binary was built from. That is why we try to reproduce the binary. We
- obtain the binary from the provider
- compile the published source code using the published build instructions into a binary
- compare the two binaries
- 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 binary we can create and the binary we can find for download 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 binary 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 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.
Application build test result
(Analysis from Android review)
Update 2024-09-19:
We attempted to build again with the knowledge that an MR has been merged regarding Emanuel’s issue. We assume that the app could be built from hereon.
We begin our manual attempt, with this Dockerfile:
FROM ubuntu:22.04
RUN apt-get update && apt-get install -y --no-install-recommends \
curl \
unzip \
git \
openjdk-17-jdk \
&& rm -rf /var/lib/apt/lists/*
ENV ANDROID_SDK_ROOT=/opt/android-sdk
ENV PATH=$PATH:$ANDROID_SDK_ROOT/cmdline-tools/latest/bin:$ANDROID_SDK_ROOT/platform-tools
ENV JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64
ENV PATH=$PATH:$JAVA_HOME/bin
RUN mkdir -p $ANDROID_SDK_ROOT/cmdline-tools
RUN cd $ANDROID_SDK_ROOT/cmdline-tools && \
curl -L --retry 5 --retry-connrefused --insecure https://dl.google.com/android/repository/commandlinetools-linux-10406996_latest.zip -o commandlinetools.zip && \
unzip commandlinetools.zip && \
rm commandlinetools.zip && \
mv cmdline-tools latest
RUN yes | sdkmanager --licenses
RUN sdkmanager "platform-tools" "platforms;android-35" "build-tools;35.0.0"
RUN sdkmanager "ndk;27.0.12077973"
RUN /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)" \
&& echo 'eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"' >> /root/.bashrc \
&& eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"
We build the docker image:
cd /tmp/manualtest_one.mixin.messenger
docker build -t mixin-image . && docker run -it --rm -v "$(pwd)":/mnt mixin-image
From there, we execute:
# cd /mnt
# git clone https://github.com/MixinNetwork/android-app.git
# cd android-app
# export JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64
# export ANDROID_SDK_ROOT=/opt/android-sdk
# export PATH=$PATH:$ANDROID_SDK_ROOT/cmdline-tools/latest/bin:$ANDROID_SDK_ROOT/platform-tools:$JAVA_HOME/bin
# yes | sdkmanager --licenses
# sdkmanager "platforms;android-31" "build-tools;31.0.0"
# ./gradlew assembleRelease --stacktrace
The complete nosbin paste
Viewable as an asciicast here.
After 3 attempts, we noticed a recurring problem whenever we tried to execute ./gradlew.
Could not resolve com.mapbox.maps:android:10.10.0.
Required by:
project :app
> Could not get resource 'https://maven.pkg.github.com/checkout/checkout-3ds-sdk-android/com/mapbox/plugin/maps-lifecycle/10.10.0/maps-lifecycle-10.10.0.pom'.
> Username must not be null!
Another user faced a similar problem in Github issues. Devs confirm a Mapbox secret token is required by one of the SDKs used to build Mixin Messenger
It’s a secret token meaning you’re expected to provide your own. To do that, you must create an account with Mapbox.
NOTE: Signing up to MAPBOX requires you input your credit card information - and tax identification number. There’s a free tier, but the credit card and tax identification number gave us pause.
We raised this concern with them on x.com.
We verified these requirements in:
Line 369:
implementation “com.mapbox.maps:android:${mapboxSdkVersion}”
Line 159:
maven { url ‘https://api.mapbox.com/downloads/v2/releases/maven’ authentication { basic(BasicAuthentication) } credentials { username = ‘mapbox’ password = project.properties[‘MAPBOX_DOWNLOADS_TOKEN’] ?: “” } }
We created an issue in their repository.
For now, we will retain the previous verdict failed to build from source
Update 2024-07-17: After almost three years, we are re-opening this for verification. The issue that was created has been closed with an MR.
Update 2021-11-17: Although the source code is public, Emanuel failed to compile it from the source with the instructions provided. See the issue.
From the Play Store description:
Mixin Messenger is an open-source cryptocurrency wallet and signal protocol messenger, which supports almost all popular cryptocurrencies.
It supports Bitcoin, Ethereum, EOS, Monero and thousands of other cryptocurrencies.
Also relevant:
Mixin Messenger is built on Mixin Network, it’s a PoS second layer solution for other blockchains. Mixin Network is a distributed second layer ledger, so you own your crypto assets. Because of this second layer, it’s normal that you can’t check your BTC address balance on a Bitcoin blockchain explorer.
More information about how its wallet functions can be found on this Zendesk article “Guides for Wallet”
We emailed the Mixin development team on September 16, 2021, to verify whether they have custody of the private keys. We await their response.
The repository is linked in the description.
It appears that this wallet is non-custodial and that source-code is available.
An issue has been made on Gitlab with the corresponding results.
Issue has been raised in MixinNetwork’s Github Issues page.
Tests performed by Daniel Andrei R. Garcia, Emanuel, Leo Wandersleb
Do your own research
In addition to reading our analysis, it is important to do your own checks. Before transferring any bitcoin to your wallet, look up reviews for the wallet you want to use. They should be easy to find. If they aren't, that itself is a reason to be extra careful.
<img src="https://walletscrutiny.com/images/social/iphone/one.mixin.messenger.png">
