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SeedSigner

Latest Release: 0.7.0 12th 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

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Custody

Private keys generated and held by user

As part of our Methodology, we ask: Is the provider ignorant of the keys?

The answer is "yes". Private keys are generated by the user on the wallet.
Read more

Source code

Public on github

Released

20th December 2020

Application build

The binary provided was reproducible from the code provided.

See test result
Tested 14th September 2023

Platform notes

There is no globally accepted definition of a hardware wallet. Some consider a paper with 12 words a hardware wallet - after all paper is a sort of hardware or at least not software and the 12 words are arguably a wallet(‘s backup). For the purpose of this project we adhere to higher standards in the hardware wallet section. We only consider a hardware wallet if dedicated hardware protects the private keys in a way that leaves the user in full and exclusive control of what transactions he signs or not. That means:

  • The device allows to create private keys offline

  • The device never shares private key material apart from an offline backup mechanism

  • The device displays receive addresses for confirmation
  • The device shares signed transactions after informed approval on the device without reliance on insecure external hardware

Passed all 12 tests

We answered the following questions in this order:

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.
Can we expect the product to ever be released?

The answer is "yes".
If the answer was "no", we would mark it as "Announced but never delivered" and the following would apply:

The answer is "no". We marked it as "Announced but never delivered".

We did not ask this question because we failed at a previous question.
If the answer was "no", we would mark it as "Announced but never delivered" and the following would apply:

Some products are promoted with great fund raising, marketing and ICOs, to disappear from one day to the other a week later or they are one-man side projects that get refined for months or even years to still never materialize in an actual product. Regardless, those are projects we consider “vaporware”.

Is this product available yet?

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

The answer is "no". We marked it as "Un-Released".

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

We focus on products that have the biggest impact if things go wrong and while pre-sales sometimes reach many thousands to buy into promises that never materialize, the damage is limited and there would be little definite to be said about an unreleased product anyway.

If you find a product in this category that was released meanwhile, please contact us to do a proper review!

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.

Is the provider ignorant of the keys?

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

The answer is "no". We marked it as "Provided private keys".

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

The best hardware wallet cannot guarantee that the provider deleted the keys if the private keys were put onto the device by them in the first place.

There is no way of knowing if the provider took a copy in the process. If they did, all funds controlled by those devices are potentially also under the control of the provider and could be moved out of the client’s control at any time at the provider’s discretion.

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 device hide your keys from other devices?

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

The answer is "no". We marked it as "Leaks Keys".

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

Some people claim their paper wallet is a hardware wallet. Others use RFID chips with the private keys on them. A very crucial drawback of those systems is that in order to send a transaction, the private key has to be brought onto a different system that doesn’t necessarily share all the desired aspects of a hardware wallet.

Paper wallets need to be printed, exposing the keys to the PC and the printer even before sending funds to it.

Simple RFID based devices can’t sign transactions - they share the keys with whoever asked to use them for whatever they please.

There are even products that are perfectly capable of working in an air-gapped fashion but they still expose the keys to connected devices.

This verdict is reserved for key leakage under normal operation and does not apply to devices where a hack is known to be possible with special hardware.

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 user verify and approve transactions on the device?

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

The answer is "no". We marked it as "Bad Interface".

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

These are devices that might generate secure private key material, outside the reach of the provider but that do not have the means to let the user verify transactions on the device itself. This verdict includes screen-less smart cards or USB-dongles.

The wallet lacks either a screen or buttons or both. In consequence, crucial elements of approving transactions is being delegated to other hardware such as a general purpose PC or phone which defeats the purpose of a hardware wallet. For big exit scams, a companion app could always request two signatures - one for the coffee you are paying and a second to empty your wallet completely. The former could be broadcast while the latter only gets collected for later use.

Another consquence of a missing screen is that the user is faced with the dilemma of either not making a backup or having to pass the backup through an insecure device for display or storage.

The software of the device might be perfect but this device cannot be recommended due to this fundamental flaw.

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

Update 2023-09-14: Seedsigner announced reproducibility with their latest release that they even gave the promising name The “It’s reproducible forever, Laura” Release. So we went and had a look how reproducible it is. After some initial hurdles, we were pointed to the correct build instructions. That looks easy. Let’s see how it goes … crossing fingers the public wifi in a café in the Bavarian countryside holds up …

$ git clone --recursive https://github.com/SeedSigner/seedsigner-os.git
Cloning into 'seedsigner-os'...
remote: Enumerating objects: 1025, done.
remote: Counting objects: 100% (398/398), done.
remote: Compressing objects: 100% (149/149), done.
remote: Total 1025 (delta 295), reused 311 (delta 240), pack-reused 627
Receiving objects: 100% (1025/1025), 1.42 MiB | 4.23 MiB/s, done.
Resolving deltas: 100% (499/499), done.
Submodule 'buildroot' (https://github.com/seedsigner/buildroot) registered for path 'opt/buildroot'
Cloning into '/home/leo/tmp/seedsigner-os/opt/buildroot'...
remote: Enumerating objects: 505256, done.        
remote: Counting objects: 100% (3/3), done.        
remote: Compressing objects: 100% (2/2), done.        
remote: Total 505256 (delta 1), reused 1 (delta 1), pack-reused 505253        
Receiving objects: 100% (505256/505256), 156.36 MiB | 11.58 MiB/s, done.
Resolving deltas: 100% (334143/334143), done.
Submodule path 'opt/buildroot': checked out '165046699ae0799a359466ce73d124127df77554'
$ cd seedsigner-os
$ git checkout 0.7.0 
Branch '0.7.0' set up to track remote branch '0.7.0' from 'origin'.
Switched to a new branch '0.7.0'
$ git submodule update --init
$ SS_ARGS="--$BOARD_TYPE --app-branch=0.7.0" docker-compose up --force-recreate --build
Creating network "seedsigner-os_default" with the default driver
Building build-images
...

… this step was already announced to take a while. And it does. The screen is flying for half an hour straight already … will it end soon? Will it take 2.5h? The 4CPUs are maxed out. Table is getting hot. … sensors occasionally reports the CPU to go above 90°C …

Anyway … one coke later it got to a result. Let’s see …

...
build-images_1  | 
build-images_1  | Device     Boot Start   End Sectors Size Id Type
build-images_1  | disk.img1  *     2048 53247   51200  25M  c W95 FAT32 (LBA)
build-images_1  | 
build-images_1  | The partition table has been altered.
build-images_1  | Syncing disks.
build-images_1  | mkfs.fat 4.2 (2021-01-31)
build-images_1  | /opt/buildroot
build-images_1  | a380cb93eb852254863718a9c000be9ec30cee14a78fc0ec90708308c17c1b8a  /opt/../images/seedsigner_os.0.7.0.pi0.img
seedsigner-os_build-images_1 exited with code 0

That hash matches the one reported on their release page. Let’s see if the binary for download actually has this hash:

$ wget https://github.com/SeedSigner/seedsigner/releases/download/0.7.0/seedsigner_os.0.7.0.pi0.img
$ sha256sum seedsigner_os.0.7.0.pi0.img images/seedsigner_os.0.7.0.pi0.img 
a380cb93eb852254863718a9c000be9ec30cee14a78fc0ec90708308c17c1b8a  seedsigner_os.0.7.0.pi0.img
a380cb93eb852254863718a9c000be9ec30cee14a78fc0ec90708308c17c1b8a  images/seedsigner_os.0.7.0.pi0.img

That looks good. This product is reproducible in the version tested with the hash provided.

Old Analysis

The Seed Signer is a truly Open Source project that lowers the barrier for entry for airgapped multi-signature cryptocurrency hardware wallets. The code is publicly available as are the instructions for assembly.

It claims to solve the following problems:

  • Creates a secure, air-gapped environment for private key generation
  • Enforces strict separation between private key storage and protocol software / internet
  • Lowers the barrier cost of multi-sig security (from several hundred to < $50)

Can the private keys be created offline?

Yes. The seed signer is airgapped.

Are the private keys shared?

No. The companion apps only get signed transactions and no keys.

Does the device display the receive address for confirmation?

Yes.

Does the interface have a display screen and buttons which allows the user to confirm transaction details?

Yes.

Is it reproducible?

SeedSigner does share binaries, so the question is if these binaries match the published and hopefully reviewed source code.

On their website there is a button labeled “DOWNLOAD VERSION 0.4.6” which does not statically link to a binary but to a JavaScript document that then initiates a download. While this is slightly suspicious, all that really matters is the hash of the downloaded file. If you and I get the same hash, we are talking about the same file.

Alternatively there is the GitHub Releases where as of now “0.4.6” is the “latest” release. Both downloads had the same sha256 hash 1e47d997484c0396d01c87664753644e91c8e7c99f64b4cbfb048cf79bb03b1a.

So … how was this file created, so we can recreate it? There is not exactly “Build Instructions”. There is only a document with Manual Installation Instructions. And that is pretty involved. Its starting point is … you need an RPi. Not necessarily an RPi Zero 1.3 and the “Raspberry Pi Lite operating system, dated 2021-05-28”. Being specific is important for reproducibility but the next steps … are many and none of which to our knowledge is meant to make reproducible modifications to the system. While many packages that are to be installed are pinned to specific versions, this instruction:

sudo apt-get update && sudo apt-get install -y wiringpi python3-pip \
  python3-numpy python-pil libopenjp2-7 git python3-opencv \
  python3-picamera libatlas-base-dev qrencode

explicitly instructs to update to whatever the latest packages are on the remote server and install the given ten packages.

We might miss something here and might give it an actual try at some point but for now we go with our educated guess that this product is not verifiable.

If you want to use thhttps://snort.social/p/npub17tyke9lkgxd98ruyeul6wt3pj3s9uxzgp9hxu5tsenjmweue6sqq4y3mglis product, do not trust the binary download. Go with the “Manual Installation Instructions” instead!

We had a little back-and-forth with the provider on Twitter.

Tests performed by Daniel Andrei R. Garcia, Leo Wandersleb

Previous application build tests

26th March 2022 0.4.5  

Disclaimer

Our Analysis is not a full code review! We plan to make code reviews available in the future but even then it will never be a stamp of approval but rather a list of incidents and questionable coding practice. Nasa sends probes to space that crash due to software bugs despite a huge budget and stringent scrutiny.

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.