As part of our Methodology, we ask:
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.But we also ask:
Discontinued products or worse, products of providers that are not active anymore, are problematic, especially if they were not formerly reproducible and well audited to be self-custodial following open standards. If the provider hasn’t answered inquiries for a year but their server is still running or similar circumstances might get this verdict, too.
The Analysis ¶
This does not represent a full code review.
Update 2021-06-16: It’s been six weeks this app is not on the App store. If it should return, please open an issue on our issue tracker!
Emanuel looked into this wallet a bit as it claims association with a pretty prominent website - bitcoin.org and indeed it is endorsed by Cobra-Bitcoin, the owner of bitcoin.org.
As Emanuel so far doesn’t write analysis, I’ll reproduce his reproduction of this wallet to also compare the result with what we get from Google Play:
mkir /tmp/testbitcoinorg
cd /tmp/testbitcoinorg
podman run --rm --volume $PWD:/app --interactive --tty frolvlad/alpine-glibc
apk update
apk add --no-cache openjdk8 git yarn
export ANDROID_SDK_ROOT="/home/appuser/app/sdk"
export ANDROID_HOME="/home/appuser/app/sdk"
export NODE_ENV="production"
mkdir -p "/home/appuser/app/sdk/licenses" "/home/appuser/app/bitcoinorg/"
printf "\n24333f8a63b6825ea9c5514f83c2829b004d1fee" > "/home/appuser/app/sdk/licenses/android-sdk-license"
cd /app
git clone https://github.com/bitcoin-dot-org/BitcoinWalletMobile/
cd BitcoinWalletMobile
git checkout v1.0
yarn install --frozen-lockfile --production
cd android
sed -i '/org.gradle.jvmargs/s/^#//g' gradle.properties
./gradlew assembleRelease
./gradlew bundleRelease
cp app/build/outputs/apk/release/app-release.apk .
cp app/build/outputs/bundle/release/app-release.aab .
So far so good, the apk and the aab got created successfully but … Emanuel stated that they use aab and we so far only could reproduce apk builds.
Let’s see how the apk build looks like:
$ unzip /path/to/Bitcoin\ Wallet\ 1.0\ \(org.bitcoin.wallet\).apk -d fromGoogle
$ unzip BitcoinWalletMobile/android/app-release.apk -d fromBuild
$ diff --recursive --brief from*
Files fromBuild/AndroidManifest.xml and fromGoogle/AndroidManifest.xml differ
Only in fromGoogle/assets: index.android.bundle
Only in fromBuild: lib
Only in fromGoogle/META-INF: BNDLTOOL.RSA
Only in fromGoogle/META-INF: BNDLTOOL.SF
Only in fromBuild/META-INF: CERT.RSA
Only in fromBuild/META-INF: CERT.SF
Files fromBuild/META-INF/MANIFEST.MF and fromGoogle/META-INF/MANIFEST.MF differ
Only in fromBuild/res: drawable-anydpi-v21
Only in fromBuild/res: drawable-hdpi-v4
Files fromBuild/res/drawable-ldpi-v4/ic_launcher_foreground.png and fromGoogle/res/drawable-ldpi-v4/ic_launcher_foreground.png differ
Only in fromBuild/res: drawable-ldrtl-hdpi-v17
Only in fromBuild/res/drawable-ldrtl-mdpi-v17: abc_spinner_mtrl_am_alpha.9.png
Only in fromBuild/res: drawable-ldrtl-xhdpi-v17
Only in fromBuild/res: drawable-ldrtl-xxhdpi-v17
Only in fromBuild/res: drawable-ldrtl-xxxhdpi-v17
Only in fromBuild/res/drawable-mdpi-v4: abc_btn_check_to_on_mtrl_000.png
Only in fromBuild/res/drawable-mdpi-v4: abc_btn_check_to_on_mtrl_015.png
Only in fromBuild/res/drawable-mdpi-v4: abc_btn_radio_to_on_mtrl_000.png
Only in fromBuild/res/drawable-mdpi-v4: abc_btn_radio_to_on_mtrl_015.png
Only in fromBuild/res/drawable-mdpi-v4: abc_cab_background_top_mtrl_alpha.9.png
Only in fromBuild/res/drawable-mdpi-v4: abc_ic_star_black_48dp.png
Only in fromBuild/res/drawable-mdpi-v4: abc_ic_star_half_black_48dp.png
Only in fromBuild/res/drawable-mdpi-v4: abc_list_pressed_holo_dark.9.png
Only in fromBuild/res/drawable-mdpi-v4: abc_list_selector_disabled_holo_dark.9.png
Only in fromBuild/res/drawable-mdpi-v4: abc_popup_background_mtrl_mult.9.png
Only in fromBuild/res/drawable-mdpi-v4: abc_scrubber_control_off_mtrl_alpha.png
Only in fromBuild/res/drawable-mdpi-v4: abc_scrubber_control_to_pressed_mtrl_000.png
Only in fromBuild/res/drawable-mdpi-v4: abc_scrubber_control_to_pressed_mtrl_005.png
Only in fromBuild/res/drawable-mdpi-v4: abc_scrubber_primary_mtrl_alpha.9.png
Only in fromBuild/res/drawable-mdpi-v4: abc_scrubber_track_mtrl_alpha.9.png
Only in fromBuild/res/drawable-mdpi-v4: abc_spinner_mtrl_am_alpha.9.png
Only in fromBuild/res/drawable-mdpi-v4: abc_tab_indicator_mtrl_alpha.9.png
Only in fromBuild/res/drawable-mdpi-v4: abc_text_select_handle_left_mtrl_dark.png
Only in fromBuild/res/drawable-mdpi-v4: abc_text_select_handle_left_mtrl_light.png
Only in fromBuild/res/drawable-mdpi-v4: abc_text_select_handle_middle_mtrl_dark.png
Only in fromBuild/res/drawable-mdpi-v4: abc_text_select_handle_middle_mtrl_light.png
Only in fromBuild/res/drawable-mdpi-v4: abc_text_select_handle_right_mtrl_dark.png
Only in fromBuild/res/drawable-mdpi-v4: abc_text_select_handle_right_mtrl_light.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_arrow.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_camera.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_collectionfocus.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_collection.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_copy.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_create.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_currency.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_do_not_loose_it.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_exit.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_eye.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_forward.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_gearfocus.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_gear.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_keep_it_safe.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_language.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_laptop.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_link.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_qrcodeicon.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_receivedbutton.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_receivefocus.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_receive.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_refresh.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_restore.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_sendbutton.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_send.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_sent.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_swap.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_tick.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_warning.png
Only in fromBuild/res/drawable-mdpi-v4: assets_images_write_it_down.png
Only in fromBuild/res/drawable-mdpi-v4: common_google_signin_btn_icon_dark_normal_background.9.png
Only in fromBuild/res/drawable-mdpi-v4: common_google_signin_btn_icon_light_normal_background.9.png
Only in fromBuild/res/drawable-mdpi-v4: common_google_signin_btn_text_dark_normal_background.9.png
Only in fromBuild/res/drawable-mdpi-v4: common_google_signin_btn_text_light_normal_background.9.png
Only in fromBuild/res/drawable-mdpi-v4: design_ic_visibility_off.png
Only in fromBuild/res/drawable-mdpi-v4: design_ic_visibility.png
Only in fromBuild/res/drawable-mdpi-v4: googleg_disabled_color_18.png
Only in fromBuild/res/drawable-mdpi-v4: googleg_standard_color_18.png
Only in fromBuild/res/drawable-mdpi-v4: ic_launcher_foreground.png
Only in fromBuild/res/drawable-mdpi-v4: node_modules_reactnavigation_stack_src_views_assets_backicon.png
Only in fromBuild/res/drawable-mdpi-v4: notification_bg_low_normal.9.png
Only in fromBuild/res/drawable-mdpi-v4: notification_bg_low_pressed.9.png
Only in fromBuild/res/drawable-mdpi-v4: notification_bg_normal.9.png
Only in fromBuild/res/drawable-mdpi-v4: notification_bg_normal_pressed.9.png
Only in fromBuild/res/drawable-mdpi-v4: notify_panel_notification_icon_bg.png
Only in fromBuild/res: drawable-xhdpi-v4
Only in fromBuild/res: drawable-xxhdpi-v4
Only in fromBuild/res: drawable-xxxhdpi-v4
Only in fromGoogle/res/xml: splits0.xml
Files fromBuild/resources.arsc and fromGoogle/resources.arsc differ
Only in fromGoogle: stamp-cert-sha256
which is certainly not a match but aab would allow certain content to be stripped and stuff missing in the version from Google Play could probably not do harm. How’s the diff ignoring those and the META-INF lines?
$ diff --recursive --brief from* | grep -v "$Only in fromBuild" | grep -v META-INF
Files fromBuild/AndroidManifest.xml and fromGoogle/AndroidManifest.xml differ
Only in fromGoogle/assets: index.android.bundle
Files fromBuild/res/drawable-ldpi-v4/ic_launcher_foreground.png and fromGoogle/res/drawable-ldpi-v4/ic_launcher_foreground.png differ
Only in fromGoogle/res/xml: splits0.xml
Files fromBuild/resources.arsc and fromGoogle/resources.arsc differ
Only in fromGoogle: stamp-cert-sha256
which is still a lot. We have to give up here and hope for the provider to help with build reproduction. In the meantime this app is not verifiable.
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.