Help spread awareness for build reproducibility
Please help us spread the word, asking BTC.com - Bitcoin Wallet to support reproducible builds via their Twitter!
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 ¶
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 http://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 email@example.com firstname.lastname@example.org 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
.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!
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
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
- 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 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.
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