Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Ok Google: please publish your DKIM secret keys

blog.cryptographyengineering.com

Post reply on HN
Print view View original

421–430 of 492 posts

Re: Ok Google: please publish your DKIM secret keys

#421

Post by baobabKoodaa »

a1369209993 wrote: post #356
baobabKoodaa wrote: post #310

Earlier quoted context omitted.

> You gave a example of a 'need' to do X that is specifically not legitimate. The example was that two parties are disputing a contract, the court is attempting to resolve the dispute, and the court has a need to authenticate the contract. Can you explain why you think that this is not a legitimate need to authenticate a document? > I'm not sure (and decline to speculate) whether you're confused or malicious or some…

> Can you explain why you think that this is not a legitimate need to authenticate a document? Because it is not legitimate for a court to treat something that was not intentionally (ie, with something other than DKIM) signed as a signed contract. If one party did not sign that contract, a DKIM 'signature' doesn't change that. Conversely, if you have a argument that the document should be treated as a valid contract…

> Because it is not legitimate for a court to treat something that was not intentionally (ie, with something other than DKIM) signed as a signed contract. If one party did not sign that contract, a DKIM 'signature' doesn't change that. Conversely, if you have a argument that the document should be treated as a valid contract despite not having been signed, the lack of DKIM 'signature' is obviously irrelevant.

Not legitimate where? In Finland, where I live, there is no restriction on the form that a contract must take. A contract can be scribbled on a napkin, a contract can be oral, and yes, a contract can be written in email. You're claiming that a document should not be treated as a valid contract if it has not been signed, but Finnish law is pretty clear that a signature is not required for a contract to be valid. Furthermore, you claim that if a signature is not a requirement for a contract to be valid, then the lack of signature is "obviously" irrelevant. This is not obvious at all, and in fact is not true at all. As you surely know, sometimes the parties to a contract dispute what was agreed upon. Having a written contract is superior to an oral contract, because it is harder to dispute what was written, than it is to dispute what was said orally. In the same vein, it is harder to dispute a written contract with signatures, than a written contract lacking signatures. And in the same vein, it is harder to dispute an email that is DKIM validated, than an email that is lacking any sender validation.

Re: Ok Google: please publish your DKIM secret keys

#422

Post by hamburglar »

baobabKoodaa wrote: post #418
cakoose wrote: post #410

Earlier quoted context omitted.

First, "innocent people can be framed" is not that simple. Without non-repudiation, you don't automatically get to frame someone for whatever. You need to provide the usual (non-DKIM) evidence of whatever you're claiming. And even with non-repudiation, you can still try and frame someone. Not having the DKIM signature might be suspicious in some circumstances, but it doesn't eliminate the possibility. Second, "innoce…

> I don't want my private communication to become public, or publicly verifiable. That doesn't mean I'm not "innocent". This is not a fringe concept: https://en.wikipedia.org/wiki/Nothing_to_hide_argument Yes, I agree we should have secure private messengers. But that has nothing to do with this discussion. First off, email is not a secure private messenger. Second, email would not become "more secure" by removing th…

"with DKIM" is the part of your argument you've failed to back up. Yes, you have a counter-example that requires authenticated emails. You don't have one that requires authenticating emails with DKIM.

Re: Ok Google: please publish your DKIM secret keys

#423

Post by garmaine »

shinigami wrote: post #179
sethgecko wrote: post #124

Earlier quoted context omitted.

Excuse my ignorance but how does someone else signing my message prove that I sent the message? Moreso if the body of the message is not being signed at all?

Good luck arguing that Gmail forged and signed an email from you.

My 14 year old who has access to my computer sent it as a prank.

Re: Ok Google: please publish your DKIM secret keys

#424

Post by baobabKoodaa »

hamburglar wrote: post #422
baobabKoodaa wrote: post #418

Earlier quoted context omitted.

> I don't want my private communication to become public, or publicly verifiable. That doesn't mean I'm not "innocent". This is not a fringe concept: https://en.wikipedia.org/wiki/Nothing_to_hide_argument Yes, I agree we should have secure private messengers. But that has nothing to do with this discussion. First off, email is not a secure private messenger. Second, email would not become "more secure" by removing th…

"with DKIM" is the part of your argument you've failed to back up. Yes, you have a counter-example that requires authenticated emails. You don't have one that requires authenticating emails with DKIM .

> "with DKIM" is the part of your argument you've failed to back up. Yes, you have a counter-example that requires authenticated emails. You don't have one that requires authenticating emails with DKIM.

That's because we aren't discussing a proposal to switch from DKIM authentication to a different method of authentication. We're discussing a proposal to abandon the partial non-repudiation property that's accidentally provided by DKIM, and replacing it with nothing.

Re: Ok Google: please publish your DKIM secret keys

#425

Post by baobabKoodaa »

hamburglar wrote: post #420
baobabKoodaa wrote: post #290

Earlier quoted context omitted.

> I think the entire point is that non-repudiation shouldn't just magically happen unless intended, so yes, this is by design, and anyone who wants to send a signed email should explicitly send a signed email. Let's not pretend that the world would move away from email if Google made this change. We both know that's not going to happen. Given that, can you explain why you think the world would be a better place when…

Nobody's talking about the world moving away from google. We're talking about the world simply not having non-repudiation built into email. A sender of an email doesn't owe you non-repudiation as a feature. Sorry if you think otherwise. Senders can add non-repudiation as a feature if they want to, which satisfies your purchase receipt scenario.

> Nobody's talking about the world moving away from google. We're talking about the world simply not having non-repudiation built into email. A sender of an email doesn't owe you non-repudiation as a feature. Sorry if you think otherwise. Senders can add non-repudiation as a feature if they want to, which satisfies your purchase receipt scenario.

Please explain to me how I can make Amazon (or any other webshop) add non-repudiable contracts to their order flow? That's right, I can't. And no, I don't think that Amazon "owes" me non-repudiable emails, but now that we have non-repudiation by accident, it's certainly nice to have, and the world would be worse off if we removed that feature and replaced it with nothing.

Re: Ok Google: please publish your DKIM secret keys

#426

Post by AntiImperialist »

throwawayffffas wrote: post #419

The author underestimates how ready people are to believe slander. Publishing of DKIM keys will only allow people to produce more convincing faked emails. If a bunch of faked emails about a political leader signed with DKIM keys were released securities experts are going to say these keys are leaked and anyone could fake those emails but by the time they do the damage will have already happened and no one would be li…

So, when one sees a photograph, do people automatically believe it? Why aren't there photoshopped images of high profile people being published everywhere as slander? Because people know that photoshop exists.

Similarly, if everyone knows that these keys have been released, people wouldn't believe slanderous email dumps.

As I said in my other comment, I fear that Google may have securely destroyed the keys because of fear of it getting stolen.

Re: Ok Google: please publish your DKIM secret keys

#427

Post by dredmorbius »

pvg wrote: post #352
stouset wrote: post #341

Earlier quoted context omitted.

I haven't the faintest why this conversation is only about politicians. I don't want a nation-state to be able to contrive fake historical signatures for my own emails .

A sufficiently powerful adversary will simply steal your emails. That's the actual real threat, not that the adversary will convincingly lie about you. That part they can already do without the benefit of your emails.

An adversary with sufficient impunity will simply lie and make things up.

DKIM without rotation and disclosure provides the capacity to do so with cryptographically provable integrity. Green's paper lists instances in which this has happened (as a proof-of-concept demmostration of the risk), and may have happened.

DKIM key rotation and public key disclosure at least denies adversaries this.

Re: Ok Google: please publish your DKIM secret keys

#428

Post by dredmorbius »

greenkey wrote: post #362
woodruffw wrote: post #84

Earlier quoted context omitted.

> 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. I don't think Matthew Green is arguing against transparency. What he's observing is that non-repudiation is a…

> Do you really want someone in 2031 to be able to contrive fake signatures for the emails of politicians in 2021? How could it be used for that purpose then if it’s proven to be unreliable? It would seem that there’s more to gain in the short-term by those that have hacked Gmail accounts by exposing this, so it seems disingenuous, which you have to know, so it seems like people are fake-goading Google, causing other…

How could it be used for that purpose then if it’s proven to be unreliable?

The distinction is in removing any doubt as to reliability.

Re: Ok Google: please publish your DKIM secret keys

#429

Post by Natanael_L »

ivanhoe wrote: post #91
blendergeek wrote: post #30

Earlier quoted context omitted.

> that so people can't use email to blackmail politicians? He mentions the politicians because those were high profile cases. This could be used against anybody, not just politicians. > It seems to me that especially when an elected official has something they don't want others to know about that it should be public knowledge. Is this true of everybody else as well? Should anybody be able to deny an email they sent i…

Other than whistleblowers and activists fighting the dictatorships (and they can work-around this), what is the case where not being able to prove who sent the email would be a good thing?

Imagine stuff like abusive relationships where one party cherry picks emails to release to hurt the other. It's not really that complicated.

Stuff like revenge porn already exists. Let's not make the problem worse.

Re: Ok Google: please publish your DKIM secret keys

#430

Post by Natanael_L »

ivanhoe wrote: post #300
bee_rider wrote: post #125

Earlier quoted context omitted.

Toward the end of the blog post, the author points out that while it often is nice to have the ability to authenticate who sent an email, nobody asked for this feature to be enabled by default on all their communications. It seems like a matter of preference, and it isn't clear that people thought about it at all. People change over time and normal human communications have a natural sunset built in as people forget…

> People change over time and normal human communications have a natural sunset built in as people forget exactly who said what. It's true, but I'm not sure it's as good thing as you believe. I was born in communism, and then later I lived through the transition and have seen many people use this exact mechanism that you mention to whitewash their biographies. People just don't remember long, and thanks to that all o…

This isn't likely very viable, though. In particular because most emails won't contain full context. You can't even really tell from digitalized text if a person in an oppressive society believes in what they're writing or are just trying to avoid suspicion, and so on.
Post reply on HN