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I wouldn't assume that nation-state attackers would be thwarted by the Secure Enclave. Organizations which can deploy taps on undersea fiber optic cables from

I wouldn't assume that nation-state attackers would be thwarted by the Secure Enclave. Organizations which can deploy taps on undersea fiber optic cables from nuclear submarines, attack centrifuges deep inside air-gapped underground nuclear facilities, etc would likely be able to mount the kinds of specialized attacks needed to break into HW trusted computing models. Something that is tamper-resistant isn't tamper-proof. It will likely take some time to develop a capacity to attack these chips, but it is not impossible in principle nor intractable.

abalone 11y ago
Hey, I updated my comment with a footnote on exactly that. Not sure if you saw it. I agree it may be possible to develop an attack against the secure enclave with a big enough budget and access to lots of sample chips to practice on. But keep in mind secure enclaves are designed to self-destruct under these circumstances, so I almost think it may entail pushing the frontier of electron microscopy and/or techniques for exposing it that are more delicate that grinding down the chip. In other words yes, I'd bet money there's a "secure enclaves" team at the NSA with a few million bucks to play with. Or teams.
- cromwellian 11y ago
  Another possibility is a tailored-access type attack further upstream the supply chain. For example, Apple relies on Samsung or TSMC to fab chips. It's possible the chips could be modified before manufacture, or after, to contain a flaw. I've read about such attacks demonstrated in principle already. There was a worry about the Chinese government executing such attacks for example. One of the downsides of the way global manufacturing works today that there's so many stages in which components can be intercepted. You don't know that the device you bought actually consists of unmodified versions of the components that were part of the original design. Could the NSA partner with the Korean government and Samsung to put a backdoor into components? I wouldn't rule it out.
  - dogma1138 11y ago
    It would be considerably cheaper to just replicate the ASIC you want to attack in your own silicon. The secure enclave isn't so magic it's just a secondary processor that handles cryptography it has it's own memory to store variable such as failed attempts. Attacking the SOC might be more complex and expensive but eventually it's exactly the same as attacking the NAND or any other integrated circuit. For all we know the NSA could (and most likely does) develop their own in circuit debuggers for common ASIC/SOC's and just dumps what ever unique values the target SOC stores and takes a crack at it. This also isn't out of the realm of possibilities for companies that specialize in in-circuit emulation, hardware design, and forensics to create as a turn key solution.
    - abalone 11y ago
      > it's exactly the same as attacking the NAND or any other integrated circuit Not really. Secure enclaves have added defenses that NAND does not. They don't have an API that lets you read their embedded secrets, for instance. You can't just hook up a debugger. You'd have to try to get at the state of its transistors with an SEM or something. But additionally some have physical defenses against delayering that will self-destruct their contents in the event of a physical compromise. So while I ultimately agree that a nation-state could potentially craft an attack against a specific design, you're understating the difficulty.
      - dogma1138 11y ago
        Hence why I said it was more complex and expensive if you are going to quote some one please do so in full. Additionally NAND doesn't have an "API", NAND mirroring works by desoldering the memory hooking it up to a device and mirroring it to another chip by flagging the mirroring bit. There are other ways to attack hardware, you do not need to get a SEM(or AFM for that matter). Devices that probe transistors on a microscopic level exist in the industry (e.g. http://www.tek.com/sites/tek.com/files/media/document/resources/Probing%20Transistors%20App%20Note.pdf http://www.tek.com/sites/tek.com/files/media/document/resour...), hence the more complex and expensive part.
- hackuser 11y ago
  > I agree it may be possible to develop an attack against the secure enclave with a big enough budget You are assuming it's perfect in conception, design and implementation. That is a very unlikely assumption for any system.
- zamalek 11y ago
  > self-destruct Is this burnt silicon, or just new configuration (genuinely curious)? I'd assume that anything but a smouldering chip is in the realm of circumvention.

abalone 11y ago

Hey, I updated my comment with a footnote on exactly that. Not sure if you saw it. I agree it may be possible to develop an attack against the secure enclave with a big enough budget and access to lots of sample chips to practice on. But keep in mind secure enclaves are designed to self-destruct under these circumstances, so I almost think it may entail pushing the frontier of electron microscopy and/or techniques for exposing it that are more delicate that grinding down the chip. In other words yes, I'd bet money there's a "secure enclaves" team at the NSA with a few million bucks to play with. Or teams.

cromwellian 11y ago
Another possibility is a tailored-access type attack further upstream the supply chain. For example, Apple relies on Samsung or TSMC to fab chips. It's possible the chips could be modified before manufacture, or after, to contain a flaw. I've read about such attacks demonstrated in principle already. There was a worry about the Chinese government executing such attacks for example. One of the downsides of the way global manufacturing works today that there's so many stages in which components can be intercepted. You don't know that the device you bought actually consists of unmodified versions of the components that were part of the original design. Could the NSA partner with the Korean government and Samsung to put a backdoor into components? I wouldn't rule it out.
- dogma1138 11y ago
  It would be considerably cheaper to just replicate the ASIC you want to attack in your own silicon. The secure enclave isn't so magic it's just a secondary processor that handles cryptography it has it's own memory to store variable such as failed attempts. Attacking the SOC might be more complex and expensive but eventually it's exactly the same as attacking the NAND or any other integrated circuit. For all we know the NSA could (and most likely does) develop their own in circuit debuggers for common ASIC/SOC's and just dumps what ever unique values the target SOC stores and takes a crack at it. This also isn't out of the realm of possibilities for companies that specialize in in-circuit emulation, hardware design, and forensics to create as a turn key solution.
  - abalone 11y ago
    > it's exactly the same as attacking the NAND or any other integrated circuit Not really. Secure enclaves have added defenses that NAND does not. They don't have an API that lets you read their embedded secrets, for instance. You can't just hook up a debugger. You'd have to try to get at the state of its transistors with an SEM or something. But additionally some have physical defenses against delayering that will self-destruct their contents in the event of a physical compromise. So while I ultimately agree that a nation-state could potentially craft an attack against a specific design, you're understating the difficulty.
    - dogma1138 11y ago
      Hence why I said it was more complex and expensive if you are going to quote some one please do so in full. Additionally NAND doesn't have an "API", NAND mirroring works by desoldering the memory hooking it up to a device and mirroring it to another chip by flagging the mirroring bit. There are other ways to attack hardware, you do not need to get a SEM(or AFM for that matter). Devices that probe transistors on a microscopic level exist in the industry (e.g. http://www.tek.com/sites/tek.com/files/media/document/resources/Probing%20Transistors%20App%20Note.pdf http://www.tek.com/sites/tek.com/files/media/document/resour...), hence the more complex and expensive part.
hackuser 11y ago
> I agree it may be possible to develop an attack against the secure enclave with a big enough budget You are assuming it's perfect in conception, design and implementation. That is a very unlikely assumption for any system.
zamalek 11y ago
> self-destruct Is this burnt silicon, or just new configuration (genuinely curious)? I'd assume that anything but a smouldering chip is in the realm of circumvention.