Show HN: The SC4-HSM, a fully open USB hardware secure module • Hacker News Board

Re: Show HN: The SC4-HSM, a fully open USB hardware secure module

#41

Post by amluto » Fri, Jul 08, 2016, 1:05 PM UTC

lisper wrote: post #7

mcpherrinm wrote: post #6

Earlier quoted context omitted.

At least in my mind, the defining attribute of an HSM is protection against physical compromise of the device. Maybe we disagree on that definition: I guess it is hardware, and it exists for security, and it's a module. I admit it's unfair to compare this with a $10,000 HSM from Thales or Safenet, of course. But it seems like a smartcard based solution might be better on that front, as they're designed to withstand p…

> smartcard Those are not at all secure against compromised hosts. > EM/RF emissions You probably don't want to use this to secure the nuclear launch codes. But I think you'd have to work pretty damn hard to get anything out of it. There are no external parts here, it's all one SoC, one that is specifically designed to keep proprietary code out of the hands of Chinese hackers. If it were easy to attack it would lose…

>> smartcard

> Those are not at all secure against compromised hosts.

How so? Certainly there are poorly designed applications on smartcards that are vulnerable, but the smartcard itself should be fine.

Re: Show HN: The SC4-HSM, a fully open USB hardware secure module

#42

Post by kabdib » Fri, Jul 08, 2016, 1:07 PM UTC

pjc50 wrote: post #35

jaekwon wrote: post #8

Awesome. One question... why STM/ARM? I'm not an expert in the available choices, but I'm generally curious about RiskV devices because they're fully open. Are the designs of this chip at least available, and audit-able, or could it contain something like Intel's HM?

Are RISCV devices actually available at all? I'm not too worried about backdoors in microcontrollers, they're too small to hide much. Are the designs of this chip at least available, and audit-able I'm not aware of any processors you can buy from current production that meet this criterion (because it would involve complete exposure of that company's IP). I suppose the fully reverse-engineered 6502 meets it.

> I'm not too worried about backdoors in microcontrollers, they're too small to hide much.

You can hide a LOT on a chip, though for embedded systems the attacks are not likely to be generic, or scale.

If I was a spook agency, I'd definitely try to compromise USB handling, at a low level. Most controllers I know of use DMA, so it's likely that sneaking in a few hundred gates would open up a whole SOC. The USB controllers are just libraries that people buy; I don't know how closely they are audited by customers.

Hook that up to a compromised PC (read about system management CPUs...) and that's the ball game.

Silicon is pretty opaque.

Re: Show HN: The SC4-HSM, a fully open USB hardware secure module

#43

Post by kabdib » Fri, Jul 08, 2016, 1:10 PM UTC

Hmmm, it has a display. This is going to last about two days in my pocket.

For the last year I've been carrying around a couple Yubikeys on my keychain. They've been through the wash at least once. They're well nigh indestructible.

I don't know how you make something capable of user interaction AND immune to keys, pocket fuzz and soapy water. It's a tall order.

Re: Show HN: The SC4-HSM, a fully open USB hardware secure module

#44

Post by slinger » Fri, Jul 08, 2016, 3:01 PM UTC

mmlopes wrote: post #20

I've been looking for something like this in a while. It would be feasible to make something like this but with a Bluetooth interface instead (I'm concerned about MITM attacks)? I've been wondering about the possibility of writing a mobile app that uses a Bluetooth HSM to sign documents. Great work and nice project by the way

Looking for a Bluetooth solution as well

Re: Show HN: The SC4-HSM, a fully open USB hardware secure module

#45

Post by lisper » Fri, Jul 08, 2016, 3:22 PM UTC

amluto wrote: post #41

lisper wrote: post #7

Earlier quoted context omitted.

> smartcard Those are not at all secure against compromised hosts. > EM/RF emissions You probably don't want to use this to secure the nuclear launch codes. But I think you'd have to work pretty damn hard to get anything out of it. There are no external parts here, it's all one SoC, one that is specifically designed to keep proprietary code out of the hands of Chinese hackers. If it were easy to attack it would lose…

>> smartcard > Those are not at all secure against compromised hosts. How so? Certainly there are poorly designed applications on smartcards that are vulnerable, but the smartcard itself should be fine.

If an attacker pwns your host they can do anything you can do. If you can access the smartcard, then the attacker can too. As soon as you plug the card in, the card is just as compromised as the host.

This is the reason that the SC4-HSM has a built-in display and user inputs. These serve the same purpose as the display on a PoS terminal, except that because they are a part of the HSM itself, they can't be compromised by an attacker who pwns the host that the HSM is plugged in to.

An attacker can still attempt a phishing attack, but this will be much, much harder. And for really mission-critical applications, an attacker would have to control every possible means of computing a secure hash on the host machine.

I should probably write a paper about this.

Re: Show HN: The SC4-HSM, a fully open USB hardware secure module

#46

Post by halomru » Fri, Jul 08, 2016, 3:35 PM UTC

kabdib wrote: post #43

Hmmm, it has a display. This is going to last about two days in my pocket. For the last year I've been carrying around a couple Yubikeys on my keychain. They've been through the wash at least once. They're well nigh indestructible. I don't know how you make something capable of user interaction AND immune to keys, pocket fuzz and soapy water. It's a tall order.

>I don't know how you make something capable of user interaction AND immune to keys, pocket fuzz and soapy water. It's a tall order.

One consumer device that has consistently delivered that is the waterproof, rugged feature phone. In fact, taking an old Samsung B2100 and writing a Java app to serve as a Bluetooth HSM probably leads to a cheap, serviceable solution.

Re: Show HN: The SC4-HSM, a fully open USB hardware secure module

#47

Post by Karunamon » Fri, Jul 08, 2016, 3:54 PM UTC

lisper wrote: post #45

amluto wrote: post #41

Earlier quoted context omitted.

>> smartcard > Those are not at all secure against compromised hosts. How so? Certainly there are poorly designed applications on smartcards that are vulnerable, but the smartcard itself should be fine.

If an attacker pwns your host they can do anything you can do. If you can access the smartcard, then the attacker can too. As soon as you plug the card in, the card is just as compromised as the host. This is the reason that the SC4-HSM has a built-in display and user inputs. These serve the same purpose as the display on a PoS terminal, except that because they are a part of the HSM itself, they can't be compromised…

I thought that the whole point of a smartcard is that your keys, once loaded, can never be extracted again, even by the host. Rather than passing secrets to the host directly, there's a miniature PKI that does request/signature, secured by a password, using a hardware pinpad if you're very serious.

Little window for error too, since screwing up the password some small number of times results in the card being blocked, and in some cases, destroyed.

Even if the host is running hostile code, the worst it could do is forge signing requests?

Re: Show HN: The SC4-HSM, a fully open USB hardware secure module

#48

Post by lisper » Fri, Jul 08, 2016, 4:05 PM UTC

Karunamon wrote: post #47

lisper wrote: post #45

Earlier quoted context omitted.

If an attacker pwns your host they can do anything you can do. If you can access the smartcard, then the attacker can too. As soon as you plug the card in, the card is just as compromised as the host. This is the reason that the SC4-HSM has a built-in display and user inputs. These serve the same purpose as the display on a PoS terminal, except that because they are a part of the HSM itself, they can't be compromised…

I thought that the whole point of a smartcard is that your keys, once loaded, can never be extracted again, even by the host. Rather than passing secrets to the host directly, there's a miniature PKI that does request/signature, secured by a password, using a hardware pinpad if you're very serious. Little window for error too, since screwing up the password some small number of times results in the card being blocked…

> screwing up the password

If the host machine is pwned then it's not hard to steal your password.

> the worst it could do is forge signing requests

Well yeah, that's true. But if the card is protecting a really sensitive asset (like your bitcoin account) then a single forged request can do an awful lot of damage.

Re: Show HN: The SC4-HSM, a fully open USB hardware secure module

#49

Post by Karunamon » Fri, Jul 08, 2016, 4:17 PM UTC

lisper wrote: post #48

Karunamon wrote: post #47

Earlier quoted context omitted.

I thought that the whole point of a smartcard is that your keys, once loaded, can never be extracted again, even by the host. Rather than passing secrets to the host directly, there's a miniature PKI that does request/signature, secured by a password, using a hardware pinpad if you're very serious. Little window for error too, since screwing up the password some small number of times results in the card being blocked…

> screwing up the password If the host machine is pwned then it's not hard to steal your password. > the worst it could do is forge signing requests Well yeah, that's true. But if the card is protecting a really sensitive asset (like your bitcoin account) then a single forged request can do an awful lot of damage.

The point being that the malware either has to horn in on a legitimate request (and I'm not sure if that's possible or not given how PKI), or issue its own request, which the user has to authorize with password, ideally out of band using a hardware pinpad.

Re: Show HN: The SC4-HSM, a fully open USB hardware secure module

#50

Post by akiselev » Fri, Jul 08, 2016, 4:23 PM UTC

captainmuon wrote: post #39

mcpherrinm wrote: post #2

Calling this an HSM is somewhat disingenuous, as it seems to contain none of the usual defenses found in a "real" hardware security module, like tamper self-destruction of key material, and likely no side-channel protection. This is essentially just putting your keys on a dedicated computer, connected over USB. That does have value, mind you. Keeping your keys isolated definitely makes it harder for malware to exfilt…

At least for me, this "HSM" makes the right trade-offs. I don't need tamper self-destruction, for example. My adversaries are either: 1) thieves of opportunity, or 2) the "world conspiracy" / nation state intelligence agencies who suddenly might decide to spy on me if the world takes a dystopian turn. For 1) tamper-proofness is total overkill. For 2), I doubt that any civilian technology would withstand a hardware at…

> I doubt that any civilian technology would withstand a hardware attack e.g. by the NSA.

You'd probably be wrong. There are several consumer accessible chips (i.e. from Atmel that you can order on digikey) that use tamper-proof silicon where the very act of opening up the package to inspect the die destroys the private key data. Even civilian tamper-proof tech is extremely robust, using physical phenomena to protect the data instead of obfuscation.

That doesn't preclude someone with the resources of the NSA from figuring it out or backdooring the design but the resources needed to defeat tamper proof devices is orders of magnitude greater than those needed to use them and that gap is constantly growing.