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What's Intel SGX Good For?

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Re: What's Intel SGX Good For?

#51

Post by woah »

vladivstok wrote: post #48
woah wrote: post #42

The two blockchain papers are so ridiculous on their face that I find it amazing that the authors were able to work on them at all (Intel funding may have helped in that regard). The gist of them is that instead of using hard computational work to secure a chain against sybil attacks, they use timeouts enforced by Intel. To get more mining power in proof of work, one has to buy a lot of hashing chips, and feed a lot…

I feel like you've misunderstood the papers, and what the motivation behind them is. The argument isn't that Intel chips are more efficient, it is that these schemes simply don't require continuous computations. As for the two schemes, you are correct about the first paper that it depends on the timeouts enforced by SGX. However, the second paper makes no such assumptions and doesn't even assume that the enclave is s…

As I understand it, the benefit of PoET is that it doesn't require the massive waste of electricity that PoW does.

What I find ridiculous is that they have roughly the same security properties as a timestamping server set up by Intel. Creating a blockchain that depends entirely on one trusted party seems pointless.

Re: What's Intel SGX Good For?

#53

Post by Spivak »

centimeter wrote: post #39
jnwatson wrote: post #28

Earlier quoted context omitted.

Part of it is community agreement. In order to mutually trust what we do on each others' machines, we give up some rights, including the ability to lie about what you executed on your own machine. It is the implicit agreement in Folding @home and many community computation projects, only this is better enforced. Peer-to-peer computation is hard to implement because of the quite hairy social aspect of requiring a trus…

> In order to mutually trust what we do on each others' machines, we give up some rights I trust what people do on their machines to the extent they can cryptographically prove it to me. Anything else is, for me, an unacceptable compromise.

Which, given that you believe that SGX hasn’t been compromised yet, is exactly what you get!

Re: What's Intel SGX Good For?

#54

Post by theamk »

johncolanduoni wrote: post #50
eqvinox wrote: post #19

Earlier quoted context omitted.

> I agree that that's an unreasonable assumption which is why we developed RRR. Out of curiosity, I would've hoped that the consensus in the cryptography community is that "secure enclaves" are pretty much snake oil to begin with... is this not the case? (I mean... for a secure enclave to actually work, you need "perfect" physical security, "perfect" software implementation inside, and "perfect" design of the cryptog…

You could apply the same logic to cryptographic systems themselves; we have very few absolute proofs of security properties for the cryptography we use for TLS and the like, so they are “imperfect” and may be vulnerable and therefore are snake oil. However I doubt you’d feel indifferent about whether a website you are sending your credit card number to uses HTTPS and stores your payment information encrypted at rest.

I'd trust much more to software in general (and TLS-based crypto in particular) compared to hardware devices.

The TLS vs SGX is a particularly bad comparison. SGX's internal design was not even published, let alone reviewed; and it already had multiple bad exploits. The TLS design and code has been reviewed by a multiple cryptographers, and the algorithm itself (not implementation) is unbroken.

Re: What's Intel SGX Good For?

#55

Post by mkj »

woah wrote: post #42

The two blockchain papers are so ridiculous on their face that I find it amazing that the authors were able to work on them at all (Intel funding may have helped in that regard). The gist of them is that instead of using hard computational work to secure a chain against sybil attacks, they use timeouts enforced by Intel. To get more mining power in proof of work, one has to buy a lot of hashing chips, and feed a lot…

Does sgx have its own oscillator or it just depends on the external clock signal for timing?

Re: What's Intel SGX Good For?

#56

Post by vladivstok »

woah wrote: post #51
vladivstok wrote: post #48

Earlier quoted context omitted.

I feel like you've misunderstood the papers, and what the motivation behind them is. The argument isn't that Intel chips are more efficient, it is that these schemes simply don't require continuous computations. As for the two schemes, you are correct about the first paper that it depends on the timeouts enforced by SGX. However, the second paper makes no such assumptions and doesn't even assume that the enclave is s…

As I understand it, the benefit of PoET is that it doesn't require the massive waste of electricity that PoW does. What I find ridiculous is that they have roughly the same security properties as a timestamping server set up by Intel. Creating a blockchain that depends entirely on one trusted party seems pointless.

The timestamps for PoET don't require centralized servers; the timers are local to the platform. RRR goes one step further and doesn't even trust local timers.

Re: What's Intel SGX Good For?

#57

Post by cyphar »

vladivstok wrote: post #56
woah wrote: post #51

Earlier quoted context omitted.

As I understand it, the benefit of PoET is that it doesn't require the massive waste of electricity that PoW does. What I find ridiculous is that they have roughly the same security properties as a timestamping server set up by Intel. Creating a blockchain that depends entirely on one trusted party seems pointless.

The timestamps for PoET don't require centralized servers; the timers are local to the platform. RRR goes one step further and doesn't even trust local timers.

I think you're missing the point being made. GP isn't saying these schemes require a central server.

The point they're making is that PoET assumes that Intel SGX actually provides the properties that Intel claims (namely that they will never produce attestation certificates for code not run in SGX). Thus there is a single party which you are trusting to provide these properties and not attack your system. If you're okay with trusting a single party then the system is equivalent (in terms of security) to having that single trusted party run a server which emits timestamps.

RRR suffers from basically the same problem -- you're trusting Intel to not produce endless fraudulent identities and thus always be chosen as the oldest miner.

Re: What's Intel SGX Good For?

#58

Post by anonymousDan »

mindslight wrote: post #43
jnwatson wrote: post #28

Earlier quoted context omitted.

Part of it is community agreement. In order to mutually trust what we do on each others' machines, we give up some rights, including the ability to lie about what you executed on your own machine. It is the implicit agreement in Folding @home and many community computation projects, only this is better enforced. Peer-to-peer computation is hard to implement because of the quite hairy social aspect of requiring a trus…

That may sound like a worthwhile goal, but it's actually ripe for abuse by exacerbating existing power imbalances. For example, right now we just laugh at websites that insisting on imposing nonsensical requirements on end users (client side form validation, insistence on using a particular browser, disable copy/paste, anti-adblock, etc). Imagine they have the power to do this and succeed . Furthermore, the actual im…

Why? SGX allows you to attest the contents of the enclave independently of the host software stack (OS/hypervisor, other apps).

Re: What's Intel SGX Good For?

#59

Post by mindslight »

anonymousDan wrote: post #58
mindslight wrote: post #43

Earlier quoted context omitted.

That may sound like a worthwhile goal, but it's actually ripe for abuse by exacerbating existing power imbalances. For example, right now we just laugh at websites that insisting on imposing nonsensical requirements on end users (client side form validation, insistence on using a particular browser, disable copy/paste, anti-adblock, etc). Imagine they have the power to do this and succeed . Furthermore, the actual im…

Why? SGX allows you to attest the contents of the enclave independently of the host software stack (OS/hypervisor, other apps).

I was speaking to the general concern.

A small sandbox isn't a full threat in the manner I laid out, just the same owner-is-hostile dynamic.

If attestation keys were only rooted in the processor itself (ie not signed by Intel/AMD) and users could load their own, the worthwhile properties of hardened hardware would be preserved without making the owner an enemy.

Re: What's Intel SGX Good For?

#60

Post by centimeter »

Spivak wrote: post #53
centimeter wrote: post #39

Earlier quoted context omitted.

> In order to mutually trust what we do on each others' machines, we give up some rights I trust what people do on their machines to the extent they can cryptographically prove it to me. Anything else is, for me, an unacceptable compromise.

Which, given that you believe that SGX hasn’t been compromised yet, is exactly what you get!

> given that you believe that SGX hasn’t been compromised yet

Who the hell would believe that?

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