Is Bluetooth a security risk for hardware wallets?

[cygan]

the following recent research paper is currently sparking debate in the Bitcoin community, as it shows that cryptographic keys can be reconstructed via radio signals under certain conditions - in some cases even from several meters away: https://s3.eurecom.fr/docs/ccs18_camurati.pdf

the study in question, however, is not new at all; it dates back to 2018. nevertheless, it is currently being discussed again on social media and raises the question of whether hardware wallets with bluetooth pose a security risk. a closer look, however, reveals that the actual risk depends heavily on the specific implementation and plays virtually no role in modern wallet designs.


https://x.com/i/status/2051307357947433043

the most important takeaway from the entire debate is therefore relatively simple. the problem isn’t bluetooth itself, but rather poor implementation.
what matters most is the separation of critical components, the secure handling of keys, and a clean architecture for the hardware wallet

[Lucius]

It is obvious that BT in combination with HW poses a risk, now we can only speculate how much of a risk there is when someone uses HW in a home environment, and how much when they use it somewhere in a public place. A theoretical attacker (hacker) sitting in a car in front of someone's house/apartment with equipment for searching and collecting data that travels wirelessly can pick up a packet of information from someone who is currently using HW with BT turned on - and there can be many more such potential attackers in a public place.

I personally don't use this type of connection in combination with HW, not only because I find it insecure, but also because I don't need it.

[satscraper]

I personally don't use this type of connection in combination with HW, not only because I find it insecure, but also because I don't need it.

Foundation claims that their Bluetooth technique implemented in Passport Prime is secure because the relevant communication “uses quantum‑resistant cryptography: CRYSTALS‑Kyber key exchange and ChaCha20‑Poly1305 messaging.” But again, NFC is still superior to any Bluetooth based approach because it is short‑range, which means that virtually no other device can get between the two devices communicating via NFC for eavesdropping. In my view HW developers should therefore eschew Bluetooth in favor of NFC.

[joniboini]

In my view HW developers should therefore eschew Bluetooth in favor of NFC.

i wonder if they put bluetooth because the demand exist. After all, some people might find convenience with connections to be a feature they need. They don't necessarily want to use BT all the time but once in a while having the option to use it would be great for them, hence why they're looking for HW with BT. As long as they're aware of the risk maybe they think the shortcoming isn't that huge.

At least it's not as horrible as storing your seed phrase online and charging a monthly payment for that.

[Pmalek]

So the problem is that the device that has Bluetooth unintentionally broadcasts sensitive data that is supposed to remain secret over its radio signals. It can happen if the different chip components are placed to close to each other. The radio picks up what the CPU processes, amplifies it, and transmits it over radio frequencies, making sensitive information obtainable form much longer distances.

I never liked the idea of Bluetooth in hardware wallets. My Jade has a Bluetooth feature but I have it turned off at a firmware level. Still, I would prefer the radio not being there at all.   

[cygan]

bluetooth is merely a communication channel. the actual vulnerability lies in the combination of wireless transmission and sensitive computations within the same chip or within a tightly integrated architecture.
for the attack to succeed, several criteria must be met simultaneously like:

• the chip must process secret keys
• it must transmit actively at the same time
• and its internal architecture must be designed so that computational processes directly influence radio transmission

however, this applies only to simple integrated chips, in which many functions are combined into a single component.
that is why some hw-makers are going out of their way to offer fully isolated devices with no wireless connectivity. these so-called 'air-gapped wallets' completely eliminate certain vulnerabilities.

[satscraper]

So the problem is that the device that has Bluetooth unintentionally broadcasts sensitive data that is supposed to remain secret over its radio signals.

Roughly yes, but the details matter.

Bluetooth chip emitted subtle RF noise while devuce was performing cryptographic operations and by analyzing the patterns in that noise they were able to reconstruct AES‑128 key. It’s likely they also performed some preliminary analysis that helped them correlate specific RF patterns with parts of the key.

[Pmalek]

Roughly yes, but the details matter.

Bluetooth chip emitted subtle RF noise while performing cryptographic operations and by analyzing the patterns in that noise they were able to reconstruct AES‑128 key. It’s likely they also performed some preliminary analysis that helped them correlate specific RF patterns with parts of the key.

The close proximity of the transmission part to the CPU area of the chip that handles sensitive data and key cryptography is the reason why the radio picked up the noise and transmitted it together with other data. The document suggests a few countermeasures. Among them is key changes, not running cryptographic operations while the Bluetooth is transmitting, or for example using a separate chip for the Bluetooth component.   

[satscraper]

Roughly yes, but the details matter.

Bluetooth chip emitted subtle RF noise while performing cryptographic operations and by analyzing the patterns in that noise they were able to reconstruct AES‑128 key. It’s likely they also performed some preliminary analysis that helped them correlate specific RF patterns with parts of the key.

The close proximity of the transmission part to the CPU area of the chip that handles sensitive data and key cryptography is the reason why the radio picked up the noise and transmitted it together with other data.  

Sure malplacing electronic parts may be the reason, but another possible cause might be glitches in the schematic responsible for powering the device. Bluetooth chip may be relatively distant from  CPU, but if feed circuits for CPU and Bluetoth are not separated, it could result in the similar effect , namely, transmission of noise that reveals the secret.

[bitmover]

the most important takeaway from the entire debate is therefore relatively simple. the problem isn’t bluetooth itself, but rather poor implementation.
what matters most is the separation of critical components, the secure handling of keys, and a clean architecture for the hardware wallet

Sad truth.

So much competition in the hardware wallet industry,  companies are pushing convenience as much as possible to get more customers, even if that costs security..

Older devices looka to be safer ones after all.

I still own a Nano S without Bluetooth and just like 320KB of memory.

[Lucius]

I'm going to digress a bit, but I'm curious about how dangerous it is to have BT turned on on a computer where you're performing crypto transactions at the same time? To me, it always seemed like a risk to be avoided, so I use wired headphones, although wireless would be much more comfortable.

[satscraper]

I'm going to digress a bit, but I'm curious about how dangerous it is to have BT turned on on a computer where you're performing crypto transactions at the same time? To me, it always seemed like a risk to be avoided, so I use wired headphones, although wireless would be much more comfortable.

You really don’t need to stress about whether Bluetooth is ON or OFF on your machine because ^AFAIK you use Passport Core to sign transactions, thefore the private keys required for this never enter your computer. So you can safely use wireless headphones if that’s more comfortable for you. Personally, I try to limit my use of such headphones not for security reasons, but for the health reasons.

[Pmalek]

You really don’t need to stress about whether Bluetooth is ON or OFF on your machine because ^AFAIK you use Passport Core to sign transactions...

I know that Lucius used a Ledger Nano S and a Ledger Nano X before. I guess that's a thing of the past after everything that has happened and been revealed about Ledger and their plans.

So you can safely use wireless headphones if that’s more comfortable for you. Personally, I try to limit my use of such headphones not for security reasons, but for the health reasons.

I am with you there. I have never owned wireless headphones. I am old-fashioned and prefer good old wires and cables. Same thing with my mouse and keyboard. 

[Lucius]

You really don’t need to stress about whether Bluetooth is ON or OFF on your machine because ^AFAIK you use Passport Core to sign transactions, thefore the private keys required for this never enter your computer. So you can safely use wireless headphones if that’s more comfortable for you. Personally, I try to limit my use of such headphones not for security reasons, but for the health reasons.

It's my cold wallet and I don't worry about using it in combination with BT, but I also have a T5 that I use occasionally as well as a few desktop hot wallets. I don't really have much to lose here, even if someone hacks me in some strange way, but I asked because I assume that any wireless data transfer has certain risks.

Nowadays, more or less everyone uses Wi-Fi, and many people don't even know how vulnerable a wireless network can be.

I know that Lucius used a Ledger Nano S and a Ledger Nano X before. I guess that's a thing of the past after everything that has happened and been revealed about Ledger and their plans.
~snip~

Honestly, I've never turned on BT on the Model X, I've always used a cable. I thought about destroying them, but I decided they could still serve as wallets that thieves would find if they were looking for something like that, or if anyone ever forced me to show them my wallet.

[Pmalek]

Honestly, I've never turned on BT on the Model X, I've always used a cable. I thought about destroying them, but I decided they could still serve as wallets that thieves would find if they were looking for something like that, or if anyone ever forced me to show them my wallet.

My Ledger Nano S still serves a purpose. I have moved my bitcoin from it though, but I don't mind keeping a few altcoins there, like Ethereum and stablecoins. Regardless of what anyone says, I won't agree that they are better off is a software hot wallet than on the Ledger. I have a Trezor 3 waiting for me in a different location that I haven't visited in years. Once I do, I will probably set it up and move those alts there, but I am not in a hurry.

[Lucius]

My Ledger Nano S still serves a purpose. I have moved my bitcoin from it though, but I don't mind keeping a few altcoins there, like Ethereum and stablecoins. Regardless of what anyone says, I won't agree that they are better off is a software hot wallet than on the Ledger. I have a Trezor 3 waiting for me in a different location that I haven't visited in years. Once I do, I will probably set it up and move those alts there, but I am not in a hurry.

You have the same opinion as your friend with the same device who still thinks Ledger is a good (safe) device - but I respect everyone's decision to believe what they want. My trust in these devices disappeared somewhere around 2020.

Recently, news has spread that a critical vulnerability has been discovered in Linux, which has existed for 9 years, and I wonder what those who have been saying for years that it is the most secure OS think now. There are no secure devices, OS or software, there are just those that are a little less and a little more secure.

[Pmalek]

You have the same opinion as your friend with the same device who still thinks Ledger is a good (safe) device - but I respect everyone's decision to believe what they want.

I guess you mean bitmover. What's my alternative right now? Ledger is the only hardware device that I currently possess with multi-coin support. I need to keep the alts there. Should I move them to a software wallet on my desktop or mobile or an exchange? No thanks. I have small amounts on my phone. I have a Trezor One that is intentionally set up with bitcoin-only firmware. So they can't go there either. Until I get my Trezor Safe 3 the alts will have to stay where they are.

Recently, news has spread that a critical vulnerability has been discovered in Linux, which has existed for 9 years, and I wonder what those who have been saying for years that it is the most secure OS think now. There are no secure devices, OS or software, there are just those that are a little less and a little more secure.

It's still safer than Windows. But if Linux had the number of users that Windows has, there would be more incentive for the bad guys to attack it and find ways to breach it. Everything can be broken. It's just a question of who is doing the breaking and how hard they want to try.

[bitmover]

You have the same opinion as your friend with the same device who still thinks Ledger is a good (safe) device - but I respect everyone's decision to believe what they want.

I guess you mean bitmover. What's my alternative right now? Ledger is the only hardware device that I currently possess with multi-coin support. I need to keep the alts there. Should I move them to a software wallet on my desktop or mobile or an exchange? No thanks. I have small amounts on my phone. I have a Trezor One that is intentionally set up with bitcoin-only firmware. So they can't go there either. Until I get my Trezor Safe 3 the alts will have to stay where they are.

Lucius said many times that he thinks a hot wallet is better than ledger models, even nano S without Bluetooth or any other feature.
I dont think he acrually believe that, this makes no sense.

I believe it is a mistake, but as he said, anyone is free to take care (or not) of their coins as they think it is best .

Bybit and top tier companies continue to use ledger as a secure device to hold billions of  dollars in crypto assets.

I wouldn't buy a new ledger now. But I dont think it is necessary to buy a trezor or jade for now. I will wait for a promotion or something like that for a Trezor, but I have no hurry.

Edit: actually I just trezor 3 for 100 usd in amazon . Very cheap price for Brazil. I will think about it in the weekend:)

[NeuroticFish]

So much competition in the hardware wallet industry,  companies are pushing convenience as much as possible to get more customers, even if that costs security..

Older devices looka to be safer ones after all.

Maybe. But I think that it's just a feeling. I mean that you can easily buy a new device that doesn't have all the (unnecessary) "convenience" "features" and will be just properly secure. It will even be cheaper, lol!

I will wait for a promotion or something like that for a Trezor, but I have no hurry.

Edit: actually I just trezor 3 for 100 usd in amazon . Very cheap price for Brazil. I will think about it in the weekend:)

Good call (on taking your time).
And imho the only minus of Trezor Safe 3 is the rather small font.

[bitmover]

Maybe. But I think that it's just a feeling. I mean that you can easily buy a new device that doesn't have all the (unnecessary) "convenience" "features" and will be just properly secure. It will even be cheaper, lol!

Which device do you suggest ? Any other one?

Trezor safe 3 doesnt have BT, which is good.

I wonder how long will they still offer support for trezor safe 3.   Probably a lot, I made a little research it was released in 2023. The biggest downside of ledger nano s for me is the end of support.

I took a look at the Bitcoin only model, as Pmalek mentioned, it isn't available in Brazil. Any benefits for not supporting altcoins?