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Trezor Safe 5

Latest Release: 2.8.7 19th September 2024

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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Released

14th June 2024

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.
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Source code

Public on github

Application build


See the last Issue we created.

If you have a binary for a version that doesn't appear on the list, you can drop the file here to register it so somebody can verify its reproducibility:

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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

Trezor Safe 5 Official Online Documentation

Trezor Safe 5 Reproducible Build Documentation (Soon to be merged)

Reproducible Build Verification for v2.8.7 (2025-01-15)

Initially, we attempted to build manually, but ran into problems when it came to signature zeroing. We filed GitHub issue 4254 so we can be aware of the appropriate values. After several tests, this got resolved and we would be closing the issue after our final test.

We were able to create a script for the Trezor Safe 5, that would automate the process.

Build Results

Built from commit 6efd33909b0ac2870773d9ef7c62c74cfa74deb9

Fingerprints:
4f6369f2932f017d8960580aec0907b73ebb4feff43fc5c6f697ddebb3a23628 build/core-R/bootloader/bootloader.bin
554c6586df79e1281dd377bfb99d7b2594dbac66d749837c6a78b9c5e0751098 build/core-R/firmware/firmware.bin
4f6369f2932f017d8960580aec0907b73ebb4feff43fc5c6f697ddebb3a23628 build/core-R-bitcoinonly/bootloader/bootloader.bin
6381f8a373f9f91a3cf4000a762b8dbf553d11a4a6d433c8863b2fa9eecfd9f1 build/core-R-bitcoinonly/firmware/firmware.bin
14b457d32f979b51482c350d0e33a3c372511010c84810b01031d752135838de build/core-T/bootloader/bootloader.bin
7f7bae53913c3a339f22adddb16db70b11bcf908af1c7a5986bae09af9d4ab62 build/core-T/firmware/firmware.bin
14b457d32f979b51482c350d0e33a3c372511010c84810b01031d752135838de build/core-T-bitcoinonly/bootloader/bootloader.bin
7bdf5de0c00c5d15c06d526a5b0d22cfd8343eb3e7aa01ee3c4ed60dd063bbf1 build/core-T-bitcoinonly/firmware/firmware.bin
01fdef4c3cfbe78d203953c65604d8d406373a0d3b26bbb8f7d3cf2250397777 build/core-T3T1/bootloader/bootloader.bin
be15ee1f4b7891dc965512455f8d17067ff54a7047e28ed06cec8d56529ab2ef build/core-T3T1/firmware/firmware.bin
01fdef4c3cfbe78d203953c65604d8d406373a0d3b26bbb8f7d3cf2250397777 build/core-T3T1-bitcoinonly/bootloader/bootloader.bin
2f58de2b7c2c29b6a2f14909ad0941e4aa9dd6d3e1416ab66c512a743b5385a9 build/core-T3T1-bitcoinonly/firmware/firmware.bin
Hash of non-signature parts downloaded/compiled standard:
65+0 records in
65+0 records out
65 bytes copied, 0.000296925 s, 219 kB/s
6d932e5200927b6eeebc9b8700effde957a9880774944bcc028b0cbac85e7f6a  trezor-t3t1-2.8.7.bin.zeroed
6d932e5200927b6eeebc9b8700effde957a9880774944bcc028b0cbac85e7f6a  build/core-T3T1/firmware/firmware.bin

Hash of non-signature parts downloaded/compiled bitcoinonly:
65+0 records in
65+0 records out
65 bytes copied, 0.0002154 s, 302 kB/s
9e1bc9773194df462a2350108da1cc4f5a70149b93affcb363c5b96c14b30a4d  trezor-t3t1-2.8.7-bitcoinonly.bin.zeroed
9e1bc9773194df462a2350108da1cc4f5a70149b93affcb363c5b96c14b30a4d  build/core-T3T1-bitcoinonly/firmware/firmware.bin

Hash of the signed firmware:
88eccdabe9085ba49eb60bd72f99d466b0209b4288d9a5963e8c351406b42773  trezor-t3t1-2.8.7.bin
b8c6b6c2187c88d32805b77da4661c65298a30a5f350f1086f888f0854c1f9ec  trezor-t3t1-2.8.7-bitcoinonly.bin

The hashes of the zeroed version of v2.8.7 matches with the signature-less built binary. The hashes of the zeroed version of v2.8.7 bitcoin-only matches with the signature-less built binary.

Version 2.8.7 of the Trezor Safe 5 is reproducible.

Review 2024-10-08

Built on the technology behind the Trezor Safe 3    , the trezor Safe 5 features the following:

  • 39 mm touchscreen (240 x 240 pixels)
  • NDA-free EAL 6+ Secure Element
  • 12-, 20-, 24- wallet backup
  • Advanced Multi-share Backup
  • Haptic feedback
  • Shipped without firmware (can be installed through USB-C using Trezor Suite)
  • Pin and passphrase protection
  • Bitcoin-only and Universal (1000 coins and tokens) variants

Tests performed by Daniel Andrei R. Garcia, keraliss

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.