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Coin Wallet - Bitcoin & Crypto

App Store
Latest Release: v 5.10.5 6th September 2023

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.

Developer

CoinSpace

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

Source code

Public on github

Released

14th December 2015

Application build

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

See test result
Tested 22nd April 2023

Distribution

App Store
4.5/5 stars

Platform notes

On the Apple App Store, there are many apps that have Bitcoin in their name or description but don’t allow the user to use Bitcoin or they don’t look like Bitcoin wallets but turn out to be. We run our tests and document our findings.

WalletScrutiny started out looking only into Android. This is because mobile wallets are the most used wallets, and Android is the most used among mobile wallets, but looking into iPhone wallets was high on the list from the start.

For Android, the reproducing build process is relatively clear; some apps did this before we started the project. For iPhone, this was not the case. As a result, iPhone app reproducibility was an open question.

We asked around. Several years passed. Nobody could reproduce any iPhone app.

At this point, we shift the burden of proof onto the providers (or Apple). If you want people to trust your app (or platform), explain how it can be audited. We will move on in the meantime and list iPhone apps with an empty reproducible section until then.

Passed 8 of 9 tests

We answered the following questions in this order:
We stopped asking questions after we encountered a failed answer.

Is this product the original?

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 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.
Is it a wallet?

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.

Is it for bitcoins?

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.

Can it send and receive bitcoins?

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.
Is the product self-custodial?

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 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.
Is the source code publicly available?

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.
Is the decompiled binary legible?

The answer is "yes".
If the answer was "no", we would mark it as "Obfuscated" and the following would apply:

The answer is "no". We marked it as "Obfuscated".

We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "Obfuscated" and the following would apply:

When compiling source code to binary, usually a lot of meta information is retained. A variable storing a masterseed would usually still be called masterseed, so an auditor could inspect what happens to the masterseed. Does it get sent to some server? But obfuscation would rename it for example to _t12, making it harder to find what the product is doing with the masterseed.

In benign cases, code symbols are replaced by short strings to make the binary smaller but for the sake of transparency this should not be done for non-reproducible Bitcoin wallets. (Reproducible wallets could obfuscate the binary for size improvements as the reproducibility would assure the link between code and binary.)

Especially in the public source cases, obfuscation is a red flag. If the code is public, why obfuscate it?

As obfuscation is such a red flag when looking for transparency, we do also sometimes inspect the binaries of closed source apps.

As looking for code obfuscation is a more involved task, we do not inspect many apps but if we see other red flags, we might test this to then put the product into this red-flag category.

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.
Can the product be built from the source provided?

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.
Does the published binary match the published source code?

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

  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 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 2023-04-22: Emanuel made progress with this product and succeeded to compile and almost reproduce version v5.10.0. He claims there were only file names that differed and implied that contents did match except for again those file names.

He used this container:

FROM docker.io/node:16-bullseye-slim

RUN set -ex; \
    apt-get update; \
    DEBIAN_FRONTEND=noninteractive apt-get install --yes -o APT::Install-Suggests=false --no-install-recommends \
        git \
        wget \
        unzip \
        openjdk-11-jdk-headless; \
    rm -rf /var/lib/apt/lists/*; \
    useradd -ms /bin/bash appuser;

USER appuser

ENV ANDROID_SDK_ROOT="/home/appuser/sdk" \
    ANDROID_HOME="/home/appuser/sdk" \
    JAVA_HOME="/usr/lib/jvm/java-11-openjdk-amd64/" \
    PATH="/home/appuser/gradle-6.9.4/bin:/home/appuser/sdk/build-tools/32.0.0/:$PATH" \
    NODE_ENV="development" \
    MOONPAY_API_KEY="pk_live_Tdc0BhIo7uIk8v9MOtWNxVJHr1WCEm" \
    SENTRY_DSN="https://039b564989724c47afb1ad407cccc7f6@o365484.ingest.sentry.io/5131667" \
    SENTRY_ORG="dummy_string_just_need_to_be_set_to_anything" \
    SENTRY_AUTH_TOKEN="dummy_string_just_need_to_be_set_to_anything" \
    CHANGELLY_REF="1c6e7ce0484f" \ 
    COMMIT="5af422a" \
    COMMIT_SHA="5af422a" \
    ORG_GRADLE_PROJECT_cdvVersionCode=3154 \
    GITHUB_RUN_NUMBER=624 \
    ZENDESK_APP_ID="4acba684eddd4f67b514c05ce516d2b9d34fa284cecaed49" \
    ZENDESK_URL="https://coinapp.zendesk.com" \
    ZENDESK_CLIENT_ID="mobile_sdk_client_f5b0609f735ecf230d0c"

RUN set -ex; \
    cd /home/appuser/; \
    git clone --single-branch --no-tags --depth 1 --branch v5.10.0 https://github.com/CoinSpace/CoinSpace/; \
    mkdir -p "/home/appuser/sdk/licenses" ; \
    printf "\n24333f8a63b6825ea9c5514f83c2829b004d1fee" > "/home/appuser/sdk/licenses/android-sdk-license"; \
    wget https://services.gradle.org/distributions/gradle-6.9.4-bin.zip; \
    unzip gradle-6.9.4-bin.zip -d /home/appuser/; \
    rm gradle-6.9.4-bin.zip; \
    wget https://dl.google.com/android/repository/commandlinetools-linux-9477386_latest.zip; \
    unzip commandlinetools-linux-9477386_latest.zip -d /home/appuser/sdk/; \
    rm commandlinetools-linux-9477386_latest.zip; \
    /home/appuser/sdk/cmdline-tools/bin/sdkmanager --sdk_root=/home/appuser/sdk/ --install "build-tools;32.0.0"; \
    cd /home/appuser/CoinSpace/; \
    npm config set @coinspace:registry https://npm.pkg.github.com; \
    npm config set "//npm.pkg.github.com/:_authToken" "ghp_github_token_only_read_packages_scope"; \
    npm ci; \
    cd /home/appuser/CoinSpace/phonegap; \
    npm ci; \
    cd /home/appuser/CoinSpace; \
    node ./cli/i18n.js --json; \
    cd /home/appuser/; \
    keytool -genkey -alias coinspace -keystore /home/appuser/CoinSpace/phonegap/release.keystore -storetype PKCS12 -keyalg RSA -keysize 4096 -storepass coinspace -keypass coinspace -validity 10000 -dname CN=IL; \
    cd /home/appuser/CoinSpace; \
    /home/appuser/CoinSpace/phonegap/node_modules/.bin/cordova telemetry off;

ENV NODE_ENV="production"

WORKDIR /home/appuser/CoinSpace

in which he ran node ./cli/build.js phonegap --env=prod --release --platform=android-play.

Update: The provider closed the issue about reproducibility, so we do not assume this app to be reproducible any time soon.

Coin Bitcoin Wallet at least implies to be non-custodial with this feature:

Secure passphrase generation (your master private key), no one else can access your Coin.Space wallet.

but other features do not sound that promising:

Get started in seconds and access your wallet from any device: app or web.

They also claim

Over 20 million Wallets users.

and are around since early 2015, so we are hopeful to find more solid information on their website because in the Playstore description there is no word about source code.

There we again see strong claims about this wallet not being custodial:

Coin does not hold your keys for you. We cannot access accounts, recover keys, reset passphrase, nor reverse transactions. Protect your keys & always check that you are on correct URL. You are responsible for your security.

But nowhere on the website is a link to a source code repository.

Searching GitHub for their applicationId com.coinspace.app we find two repositories, with one looking promising: One of the latest commits is tagged v2.16.3 which is exactly the version we see on Google Play.

Unfortunately there is nothing in terms of build instructions. Given there are two open issues, issue 14 and issue 17 asking about how to make this work, not specifically asking about Android but seeing these issues remaining unresolved in a year and almost two years I will postpone this analysis and conclude for now that this wallet is not verifiable.

Update: The developer replied to our request to resolve the issues we had but he closed the issue commenting:

Perhaps, it didn’t match because we don’t publish here our private parameters which we use for build. But you can be sure that our tags match App on Google Play store.

which was not our issue.

We are tempted to just try stuff with the Docker file there but our mission statement is that it should be easily reproducible which definitely includes not having to guess and so we remain until further notice with our prior verdict: not verifiable.

Tests performed by Leo Wandersleb

Previous application build tests

16th December 2019 v2.16.3  

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.