Passed all 7 tests
We check each wallet from its code to the app on your device, asking these questions in order:
The answer is "yes".
If the answer were "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 were "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 were "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 were "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 same goes for off-ramps that hold no balance at all: bitcoin (or gift cards) go in and fiat goes straight out to your bank. An off-ramp that keeps your fiat until you cash out is a wallet, just not for Bitcoin. One that keeps a bitcoin balance you can’t send out is ‘Can’t send or receive bitcoins’.
The answer is "yes".
If the answer were "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 were "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.
A product that can send and receive other coins but only tracks Bitcoin addresses read-only is a wallet, just not for Bitcoin, so it gets this verdict. ‘Not a wallet’ is for products that hold no coins at all, such as pure portfolio trackers.
The same goes for off-ramps that credit your bitcoin to a fiat balance you later cash out: the app holds your money, but not as bitcoin.
The answer is "yes".
If the answer were "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 were "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 were "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 were "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.
Balances on operator-dependent layers (Spark, Ark and similar) are judged by one question: “Can a user, with only what the app gives them and expecting help from nobody, actually force their money onto the Bitcoin blockchain?” Such a balance counts as self-custodial only for the part that the app itself shows the user could recover this way, calculated without network access at a fee rate the user chooses, and only once a recovery from that app has been demonstrated, because the app decides how the balance is split and therefore how much of it can come back. The rest of the balance is considered custodial.
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 were "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 were "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.Distribution
Build Verifications
Check your file
Build Verifications
As far as we know, iPhone apps cannot be reproduced. Nobody has managed to build an iPhone app from its source code and get the same binary that the App Store delivers, so there is nothing to verify here.
Update 2026-10-30: The wallet.btc.com website is gone, and the btc.com home page now advertises AI computing futures and GPU resources instead of a wallet.
Android
Hierarchically Deterministic
All accounts and keys are derived from one masterseed as defined in BIP 32, BIP 39, BIP 44, BIP 49, BIP 84 and BIP 86. While some wallets might use different definitions and not all support SegWit or Taproot, we only consider this feature as given if
- the backup is a BIP 39 mnemonic
- the funds are recoverable on a competitor’s product correctly implementing those standards
- no address reuse
- simple backup
- no vendor lock-in
Why we list it for this wallet
HD wallet technology allowing you to create an unlimited number of addresses
Source: README
Multi Signature
Bitcoin allows to define addresses controlled by more than one private key. Two-of-three for example would mean that any two of a list of three private keys would be required to send coins from this address.
With keys from distinct devices or users, an attacker would have to compromise multiple devices or users at once. Multi signature thus allows to protect against one device catching a virus, one wallet having a backdoor (if the multi signature works across different providers’ wallets), one hardware wallet not being trusted (if hardware wallets can be used for multi signature), etc.
- There are no good standards yet for multi signature accounts. This might mean that an account that works with one provider’s wallet won’t load in any other wallet which can complicate recovery should that wallet go out of business.
- Using Multi Signature results in bigger and thus more expensive transactions.
- Using Multi Signature accounts makes it easier for blockchain analysis companies to follow the trail of a wallet.
- Multi Signature accounts require backups of additional descriptors, making financial loss from user error more likely.
Why we list it for this wallet
2-of-3 Multisig technology so you always remain in control of your coins
Source: README
Free and Open Source (FOSS)
The wallet’s source code is published under a license approved by the Open Source Initiative (OSI) — such as MIT, GPL, Apache, or AGPL — allowing anyone to inspect, modify, and redistribute it. This is a prerequisite for independent security audits and reproducible builds. Licenses that are merely “source available” but not OSI-approved (e.g., those with Commons Clause restrictions, commercial use prohibitions, or other non-free terms) do NOT qualify. Reproducible builds are not sufficient alone.
-
Transparency: Anyone can verify what the code does — including whether it contains backdoors, bugs, or privacy-violating behavior.
-
Community auditing: More reviewers means vulnerabilities are more likely to be found and fixed.
-
Forkability: If the project is abandoned or goes rogue, the community can fork and continue it.
FOSS alone does not guarantee security. The released binary must also be reproducible from the public source to ensure users are actually running the code that was audited.
Camera for Secure Transactions
Camera functionality in Bitcoin hardware wallets, represents a significant advancement in wallet security and data transmission. These wallets use their built-in cameras to scan QR codes, enabling a secure and efficient method for data exchange and transaction signing. The camera-based approach is integral to maintaining an air-gapped environment, meaning the wallet does not rely on potentially vulnerable USB or Bluetooth connections for communication. The process involves creating an unsigned transaction as a QR code using a compatible wallet app. This QR code is then scanned by the hardware wallet’s camera. Inside the wallet, the transaction is securely signed using the stored private key. The signed transaction is subsequently displayed as a new QR code on the wallet, which can then be scanned back by the app to broadcast it to the blockchain network. This method of using a camera for QR code scanning and transmission ensures that the private keys remain solely within the hardware wallet, significantly bolstering security against remote attacks. It also enhances privacy, as the wallet does not directly connect to the internet or other devices, thereby reducing exposure to potential vulnerabilities.
- Enhanced security by maintaining an air-gapped environment
- Increased privacy as the wallet does not directly connect to the internet
- User-friendly transaction process with QR code scanning
This app claims:
- Bitcoin (BTC) & Bitcoin Cash (BCH) support
- 100% control of your private keys
so it’s a self-custodial BTC wallet. And it’s also open source:
This wallet is a free and open source software. You can view the code on GitHub at https://github.com/blocktrail/blocktrail-wallet.
That’s great but can we reproduce the app?
On Google Play the “current version” is 4.4.7 and on GitHub we find a tag for that.
The Readme.md also contains compile instructions. Let’s do this:
$ git clone https://github.com/blocktrail/blocktrail-wallet
$ cd blocktrail-wallet/
$ git checkout v4.4.7
$ docker run -it --volume $PWD:/mnt --workdir /mnt --rm beevelop/cordova bash
root@f74eea3c3d23:/mnt# npm install -g npm # make sure npm is latest version
root@f74eea3c3d23:/mnt# npm_config_engine_strict=false npm install -g ionic@4.3.1 cordova@8.1.2 gulp
root@f74eea3c3d23:/mnt# npm install
(node:39) ExperimentalWarning: The fs.promises API is experimental
npm ERR! code 1
npm ERR! path /mnt/node_modules/@sentry/cli
npm ERR! command failed
npm ERR! command sh -c node scripts/install.js
npm ERR! Error: Command failed: /mnt/node_modules/@sentry/cli/sentry-cli --version
npm ERR! error: Failed to load .sentryclirc file from the home folder.
npm ERR! caused by: Permission denied (os error 13)
npm ERR! A complete log of this run can be found in:
npm ERR! /root/.npm/_logs/2021-03-05T02_14_24_795Z-debug.log
so as .sentryclirc apparently is a file that has to be in the home folder with some sort of credentials, we probably can’t build the project without this further step and conclude the app is not verifiable.
Apart from there being source code it is worth mentioning that the app was not updated since July 2019 and many 1* ratings complain about financial loss!
iPhone
Hierarchically Deterministic
All accounts and keys are derived from one masterseed as defined in BIP 32, BIP 39, BIP 44, BIP 49, BIP 84 and BIP 86. While some wallets might use different definitions and not all support SegWit or Taproot, we only consider this feature as given if
- the backup is a BIP 39 mnemonic
- the funds are recoverable on a competitor’s product correctly implementing those standards
- no address reuse
- simple backup
- no vendor lock-in
Why we list it for this wallet
HD wallet technology allowing you to create an unlimited number of addresses
Source: README
Multi Signature
Bitcoin allows to define addresses controlled by more than one private key. Two-of-three for example would mean that any two of a list of three private keys would be required to send coins from this address.
With keys from distinct devices or users, an attacker would have to compromise multiple devices or users at once. Multi signature thus allows to protect against one device catching a virus, one wallet having a backdoor (if the multi signature works across different providers’ wallets), one hardware wallet not being trusted (if hardware wallets can be used for multi signature), etc.
- There are no good standards yet for multi signature accounts. This might mean that an account that works with one provider’s wallet won’t load in any other wallet which can complicate recovery should that wallet go out of business.
- Using Multi Signature results in bigger and thus more expensive transactions.
- Using Multi Signature accounts makes it easier for blockchain analysis companies to follow the trail of a wallet.
- Multi Signature accounts require backups of additional descriptors, making financial loss from user error more likely.
Why we list it for this wallet
2-of-3 Multisig technology so you always remain in control of your coins
Source: README
Free and Open Source (FOSS)
The wallet’s source code is published under a license approved by the Open Source Initiative (OSI) — such as MIT, GPL, Apache, or AGPL — allowing anyone to inspect, modify, and redistribute it. This is a prerequisite for independent security audits and reproducible builds. Licenses that are merely “source available” but not OSI-approved (e.g., those with Commons Clause restrictions, commercial use prohibitions, or other non-free terms) do NOT qualify. Reproducible builds are not sufficient alone.
-
Transparency: Anyone can verify what the code does — including whether it contains backdoors, bugs, or privacy-violating behavior.
-
Community auditing: More reviewers means vulnerabilities are more likely to be found and fixed.
-
Forkability: If the project is abandoned or goes rogue, the community can fork and continue it.
FOSS alone does not guarantee security. The released binary must also be reproducible from the public source to ensure users are actually running the code that was audited.
Update 2022-02-22: This app is not available anymore.
The Android analysis above applies to the iPhone app too.
Community Opinions
These comments are contributed by Nostr users.
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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.