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Single random bit flip causes error in certificate transparency log

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Re: Single random bit flip causes error in certificate transparency log

#111

Post by eloff »

noduerme wrote: post #103
drumbaby wrote: post #93

Earlier quoted context omitted.

I remember an older less-computer savvy gentlemen asking for support because "the program isn't working", when after a few questions we realized his computer won't boot up (screen dark, etc.). We thought his terminology was all screwed up. But now I realize he just lacked the necessary PR skill. He should have said that "the program isn't working" is a well-known term of art for power users such as himself. The fact…

You're saying you have to engineer chip components so they're small enough not to be hit as often by cosmic rays, but large enough to avoid quantum fluctuations? Are quantum fluctuations something Intel is dealing with regularly as they get down under 3nm?

Yes, quantum tunneling (an electron "teleporting" into or out of transistors) has been an issue everyone has had to design around for multiple process nodes now.

Re: Single random bit flip causes error in certificate transparency log

#112

Post by belter »

willis936 wrote: post #87
fulafel wrote: post #30

Earlier quoted context omitted.

These things exist, using trade names like chipkill or lockstep memory. Though they don't need to sacrifice half of the memory chips to get good error recovery properties. Note that this is still not end-to-end protection of data integrity. Bit flips happen in networking, storage, buses between everything, caches, CPUs, etc. See eg [1] [1] https://arxiv.org/abs/2102.11245 Silent Data Corruptions at Scale (based on em…

Checksumming filesystems and file transfer protocols cover many cases. SCP, rsync, btrfs, and zfs all fix this problem. As for guaranteeing the computed data is correct: I know space systems often have two redundant computers that calculate everything and compare results. It's crazy expensive and power demanding, but it all but solves the problem.

If they have two computers and results differ, how do they decide which one is correct ? ;-)

Re: Single random bit flip causes error in certificate transparency log

#113

Post by [deleted] »

myself248 wrote: post #56
ben_w wrote: post #47

Earlier quoted context omitted.

Radiation hardening is basically everything you can manage with the weight limit: https://en.wikipedia.org/wiki/Radiation_hardening IIRC nobody is currently using magnetic fields for shielding, I don’t know if that’s due to insufficient effectiveness, power consumption, or unwanted interactions e.g. with Earth’s magnetosphere.

I've always wondered about that. Seems to me that if you can shield one side from the sun's heat and expose the other side to the cold of space, an MRI magnet's superconductors should be quite happy with the temperature. A big ol' magnet would be a pain to charge up once, and then provide long-term shielding.

[deleted]

Re: Single random bit flip causes error in certificate transparency log

#114

Post by dredmorbius »

bloopernova wrote: post #4

Layman question: Is it possible to shield electronics against cosmic rays? Or is it like a neutrino thing, where they just go through everything? (But neutrinos barely interact, correct?)

The problem isn't cosmic rays, per se, it's the issues created by any single-instance modification of a record.

The general solution here is to store multiple redundant copies of data and checksums of those data, in order that lack-of-consistency can be determined and the specific records which are considered suspect can be clearly identified.

In general, a record is a persistence of a pattern through time subject to entropic forces.[1] Given that modifications to records are typically random events, keeping (and continuously integrity-checking) multiple copies of those records is the best general defence, not guarding against one specific variety of modification in a single instance of a record.

________________________________

Notes:

1. The symmetric statement of signals is that they are persistence of a pattern through space subject to noise. See: https://news.ycombinator.com/item?id=27604073

Re: Single random bit flip causes error in certificate transparency log

#115

Post by diegoperini »

caspper69 wrote: post #25
dijit wrote: post #21

Earlier quoted context omitted.

These are all very fair statements but there’s no guarantee that ECC memory was even used. Computers typically fail open when ECC is potentially present but not available. People also cite early stage google and intentionally do not buy ECC components, running more consumer hardware for production workloads. Even if google later recanted that theology.

It’s always humorous to me when people use the term theology in situations such as this; it makes me wonder, as human mental bandwidth becomes more strained and we increase our specializations to the n-th degree, what will constitute theology in the future? Food for thought.

Future is already here and we call it consensus. Trusting your peers, believing they are honest and proficient in their respective fields is a natural human response to the unknown phenomena.

Re: Single random bit flip causes error in certificate transparency log

#116

Post by [deleted] »

drumbaby wrote: post #93
juped wrote: post #24

Earlier quoted context omitted.

"cosmic rays" are more of a well-known term of art for "single bit flipped with unknown hardware cause" than a reference to literal cosmic rays

I remember an older less-computer savvy gentlemen asking for support because "the program isn't working", when after a few questions we realized his computer won't boot up (screen dark, etc.). We thought his terminology was all screwed up. But now I realize he just lacked the necessary PR skill. He should have said that "the program isn't working" is a well-known term of art for power users such as himself. The fact…

[deleted]

Re: Single random bit flip causes error in certificate transparency log

#118

Post by belter »

cletus wrote: post #67

Cosmic-ray bit flipping is real and it has real security concerns. This also makes Intel's efforts at market segmentation by not having ECC support in any consumer CPUs [1] even more unforgivable and dangerous. Example: bitsquatting on domains [2]. [1]: https://arstechnica.com/gadgets/2021/01/linus-torvalds-blame... [2]: https://nakedsecurity.sophos.com/2011/08/10/bh-2011-bit-squa...

Indeed. See this one for the results of Bit-squatting the Windows Update domains:

"DEFCON 19: Bit-squatting: DNS Hijacking Without Exploitation"

https://youtu.be/aT7mnSstKGs

Re: Single random bit flip causes error in certificate transparency log

#119

Post by lima »

jart wrote: post #65

The push for crypto without ecc ram is a nonstop horror show. Software under normal circumstances is remarkably resilient to having its memory corrupted. However crypto algorithms are designed so that a single bit flip effectively changes all the bits in a block. If you chain blocks then a single bit flip in one block destroys all the blocks. I've seen companies like msps go out of business because they were doing cr…

Distributed, byzantine fault tolerant state machines solve that. At worst, a single node will go out of sync.

Re: Single random bit flip causes error in certificate transparency log

#120

Post by lima »

ajross wrote: post #110
jart wrote: post #65

The push for crypto without ecc ram is a nonstop horror show. Software under normal circumstances is remarkably resilient to having its memory corrupted. However crypto algorithms are designed so that a single bit flip effectively changes all the bits in a block. If you chain blocks then a single bit flip in one block destroys all the blocks. I've seen companies like msps go out of business because they were doing cr…

> The push for crypto without ecc ram is a nonstop horror show That's a bit hyperbolic. First, ECC doesn't protect the full data chain, you can have a bitflip in a hardware flip flop (or latch open a gate that drains a line, etc...) before the value reaches the memory. Logic is known to glitch too. Second: ECC is mostly designed to protect long term storage in DRAM. Recognize that a cert like this is a very short-ter…

> This is a failed cert, which is a failure that can be reasonably easily handled by manual intervention.

This isn't a misissued cert that can be revoked, it permanently breaks the CT log in question since the error propagates down the chain.

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