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Ok Google: please publish your DKIM secret keys

blog.cryptographyengineering.com

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Re: Ok Google: please publish your DKIM secret keys

#41

Post by mthoms »

hashtagmarkup wrote: post #28
mthoms wrote: post #23

Earlier quoted context omitted.

The threat is not limited to politicians. Anyone (including you and your family members) could be blackmailed or otherwise publicly embarrassed.

> The threat is not limited to politicians. Anyone (including you and your family members) could be blackmailed or otherwise publicly embarrassed. ... for what they actually did. You think the solution is allowing people to be blackmailed or otherwise publicly embarrassed for things they didn't do, while removing their ability to verify that they didn't do them?

You're misunderstanding how this works.

You can't be blackmailed by someone who has no plausible evidence.

Re: Ok Google: please publish your DKIM secret keys

#42

Post by RcouF1uZ4gsC »

One thing that Google publishing their DKIM rotated keys is take fake news to a new level.

Basically anybody could use those signing keys to fake email from a politician or celebrity. Imagine the headlines “Celebrity X account hacked, here are the emails, cryptographically verified by Google”

Of course, informed people will know that anybody could have faked them, but I would guess normal people would be fooled. In addition, there is no way to say the emails are definitely fake. At least now, we can tell between actual leaked emails and fake emails.

Re: Ok Google: please publish your DKIM secret keys

#44

Post by nevinera »

nevinera wrote: post #40

If you have nothing to hide, you have nothing to fear! Privacy schmivacy.

I personally am absolutely confident that every email I sent during college and my adolescence would merely shine brighter light on the perfection of my soul. It sounds like the rest of you should probably have behaved better.

Re: Ok Google: please publish your DKIM secret keys

#45

Post by nullc »

Meanwhile, the IETF is speccing more messaging protocols with non-repudiation and HN users seem to be cheering that shortcoming along: https://news.ycombinator.com/item?id=25100316

I think it's kind of unfortunate that there are many people that suddenly care when its powerful people or their families that are getting caught out by DKIM, these aren't the people who need protection from it the most. No one would even care if the Hunter Biden related emails passed DKIM except for the widespread allegation that they were fake, and no one still cares because conversation about them passing DKIM is widely suppressed (including on HN, unfortunately, where a post about it was immediately flagged). Oh well, I suppose it's like when the ACLU used to defend awful speech for the sake of defending free speech because those were the cases available which could make an impact.

Unfortunately publishing DKIM secret keys only goes so far towards avoiding accidental non-repudiation: Recipients can cryptographically timestamp the signatures before the keys are published. ... and doing so already makes sense independent of DKIM. In fact, one of the ways that the public was able to prove that the outdated google DKIM key was a real key was that we were able to find cryptographically timestampped google signed emails from back when that key was still in use.

Better than key publication is to avoid having a non-repudiateable stamp to begin with. This is much easier in the context of end-to-end two-party interactive protocols, but I believe is still possible for multiparty protocols.

The analog for DKIM wouldn't work so well unfortunately, because DKIM isn't end to end. E.g. DKIM could be changed so that the signature demonstrated that either the sending server or the recipient server signed the message-- this would be just as good for anti-spam, but really wouldn't improve the non-repudiation in most cases. Contrast that with applying the same approach to end-to-end messaging, where it gives you pretty strong non-repudiation.

Re: Ok Google: please publish your DKIM secret keys

#46

Post by whimsicalism »

mthoms wrote: post #23
hpoe wrote: post #18

So the author's central thesis essentially seems to boil down to that leaked emails were able to be cryptographically verified, because of DKIM and so we should prevent that so people can't use email to blackmail politicians? Ultimately I prefer the more information that we can get on politicians available. It seems to me that especially when an elected official has something they don't want others to know about that…

The threat is not limited to politicians. Anyone (including you and your family members) could be blackmailed or otherwise publicly embarrassed.

I propose gouging out everyone's eyes, that way they can't see you do anything potentially embarrassing - thus making blackmail harder.

Re: Ok Google: please publish your DKIM secret keys

#47

Post by bluu00 »

xbar wrote: post #25

I think this is a shameful argument. Non-repudiation over time is a truly powerful property of DKIM'd email for a great many uses outside of blackmail. Calling for the ability to remove it during the years 2016-2020 in order to "protect politicians from blackmail" is not only of deeply questionable value but of suspect motivation. Who is the author interested in protecting?

your arguement seriously makes the whole _privacy arguement_ seem futile.

what about a _telegram_ message?

Re: Ok Google: please publish your DKIM secret keys

#48

Post by hyperpape »

xbar wrote: post #25

I think this is a shameful argument. Non-repudiation over time is a truly powerful property of DKIM'd email for a great many uses outside of blackmail. Calling for the ability to remove it during the years 2016-2020 in order to "protect politicians from blackmail" is not only of deeply questionable value but of suspect motivation. Who is the author interested in protecting?

"An accident of the past few years is that this feature has been used primarily by political actors working in a manner that many people find agreeable — either because it suits a partisan preference, or because the people who got “caught” sort of deserved it.

But bad things happen to good people too. If you build a mechanism that incentivizes crime, sooner or later you will get crimed on."

Re: Ok Google: please publish your DKIM secret keys

#49

Post by hyperpape »

whimsicalism wrote: post #46
mthoms wrote: post #23

Earlier quoted context omitted.

The threat is not limited to politicians. Anyone (including you and your family members) could be blackmailed or otherwise publicly embarrassed.

I propose gouging out everyone's eyes, that way they can't see you do anything potentially embarrassing - thus making blackmail harder.

This is a helpful comment because not having DKIM is in the same range of bad outcomes as having your eyes gouged out.

Re: Ok Google: please publish your DKIM secret keys

#50

Post by hyperpape »

hammock wrote: post #29

Perversely, this solution could result in MORE emails being hacked MORE OFTEN. Allow me to explain. If a hacker were to retrieve some emails before the DKIM key was made public, they could then sign their hacked emails with their own timestamped signature, proving that they are in fact authentic (since the signed timestamp shows that they were retrieved before the DKIM key was released). Therefore, by rotating the DK…

Your threat model appears to be that most email providers are hacked a substantial percent of the time, right? What defenses of anything are going to work with that threat model?
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