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What's the matter with PGP?

blog.cryptographyengineering.com

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Re: What's the matter with PGP?

#21

Post by jimktrains2 »

nodata wrote: post #14
exelius wrote: post #8

Earlier quoted context omitted.

I think the argument is that PGP is so difficult to use that by and large people just won't bother. Yes, transparent key systems would likely be less secure than PGP. If the usability were significantly better and people used them, that is better than the alternative of using nothing. For many of these solutions, there is a window of vulnerability surrounding the key exchange that closes if you aren't snooping traffi…

When I ask people for their e-mail address, they give it to me. When I ask them to verify their pgp key, it's less easy. How could the verification of the key be built into the address they give me? Something DNSSEC based I guess.

Why is it not easy to verify a key (fingerprint)? Put it on a business card with the email address or read it over the phone?

Also, DNSSEC isn't much more secure than our current CA system.

Re: What's the matter with PGP?

#23

Post by beagle3 »

rmoriz wrote: post #19

In my opinion, mail crypto needs to become mainstream usable. E.g. even trivial contents should be encrypted by default and this should be usable by default. Currently, S/MIME does a better job than PGP. While the CA-model seems to be broken in most X.509 use cases, like TLS/SSL, where a duplicate certifcate can be used to do a man-in-the-middle-attack, this does not really affect S/MIME, especially after both partie…

The "global CA" model is bust. How it was ever considered usable is beyond me, but we now have more than a decade of experience seeing just how bad it is. It is utterly, fundamentally broken and easily subverted by state actors.

For now, the only reasonably usable secure key exchange method seems to be what WhisperSystems are doing on their phone app (safe against MITM if the parties know each other, and very hard to MITM even if not - especially not automatically).

Re: What's the matter with PGP?

#26

Post by DanBC »

nikrdc wrote: post #9
bdamm wrote: post #5

Earlier quoted context omitted.

PGP is only trustworthy if both parties treat key management with the utmost severity, and if everyone in the conversation maintains the integrity of a given thread (in the email case). There are a precious few individuals for whom I have that level of trust in their management of their private key. I could not even trust my wife to manage a hardware key that I gave her, it would fall apart immediately; "I cannot use…

Can you (or anyone else) point me and others to a good text on properly handling keys? Thanks!

I would freaking love it if some good designer with technical knowledge, or help from technical colleagues, would create simple flowcharts of "How to use Encryption".

Each chart would be one page. It would walk a user through one step of using a PGP / GPG. It would include links to in-depth reading.

The final sheet would be walking through common mistakes that users make.

This is one of the things I'd pay for if I had FU money. I'm sort of tempted to kickstart the idea.

Re: What's the matter with PGP?

#27

Post by ef4 »

Yes, usability is the problem. But none of these proposed solutions manage to actually solve the usability problem without throwing out the security.

We really do need to let users manage trust, because trust is a rich concept. And humans are actually really good at trust, because we've been thriving and competing with each other in complex social situations for a long time.

The trick is finding ways to recruit people's evolved trust behaviors into an electronic context. That is, can we build meaningful webs of trust through repeated social interactions, just like in real life?

So it's not the mail client vendors who are best positioned to solve the problem, it's the social networks.

(Whether they want to solve the problem is a separate question.)

Re: What's the matter with PGP?

#28

Post by bradleyjg »

nodata wrote: post #14
exelius wrote: post #8

Earlier quoted context omitted.

I think the argument is that PGP is so difficult to use that by and large people just won't bother. Yes, transparent key systems would likely be less secure than PGP. If the usability were significantly better and people used them, that is better than the alternative of using nothing. For many of these solutions, there is a window of vulnerability surrounding the key exchange that closes if you aren't snooping traffi…

When I ask people for their e-mail address, they give it to me. When I ask them to verify their pgp key, it's less easy. How could the verification of the key be built into the address they give me? Something DNSSEC based I guess.

Either you need a trusted third party or you need to pass something that looks like (at best): 4UpbRAXYMgrESrAwiLPYymNNni1hwyL2JEK7zz2SN52t

You could do that by printing it on a business card or reading it over the phone, and then the other guy is going to have to type it in somewhere.

The reason trusted third party keeps on coming up, despite all the myriad fundamental problems, is exactly because slinging that around is so unattractive.

Re: What's the matter with PGP?

#29

Post by ef4 »

nikrdc wrote: post #9
bdamm wrote: post #5

Earlier quoted context omitted.

PGP is only trustworthy if both parties treat key management with the utmost severity, and if everyone in the conversation maintains the integrity of a given thread (in the email case). There are a precious few individuals for whom I have that level of trust in their management of their private key. I could not even trust my wife to manage a hardware key that I gave her, it would fall apart immediately; "I cannot use…

Can you (or anyone else) point me and others to a good text on properly handling keys? Thanks!

See the [GNU Privacy Handbook](https://www.gnupg.org/gph/en/manual.html).

Re: What's the matter with PGP?

#30

Post by matthewdgreen »

tptacek wrote: post #3

At one point in this essay, Matt suggests that every successful end-to-end encryption scheme has employed transparent (or "translucent") key management. What he's referring to is the idea behind, say, OTR: two people can use it without the key handshake required by PGP. Matt is wrong about this. He's being victimized by a pernicious fallacy. It certainly appears that the most "successful" cryptosystems have transpare…

Hi Thomas. I used to think this way too. I think this is certainly a fine way to think about things if your goal is to keep encrypted email deployment limited to the 3-4% of email users who are either technical experts with nothing to say and/or people who are sending obviously sensitive documents. It doesn't scale much beyond that.

Moreover, I would argue that a 'translucent' key management infrastructure /can/ be better in all ways than PGP. For example, imagine that Google provided a transparent key distribution service for all its users, but also allowed you to verify key fingerprints manually before sending messages. Congratulations -- for users who care, you've got something that works every bit as well as PGP. Everyone else isn't sending plaintext! Sure an attacker can compromise them, but it requires an expensive MITM attack. They have to be targets a priori, not after the fact. I'm struggling to see how anyone is worse off here, except through the nebulous reasoning that 'making things easy' makes people careless. Making things hard definitely makes people careless -- I've seen this firsthand.

But more to the point, even paranoid users have a lot of options that are better than PGP. Using ZRTP to establish secure channels is a very safe way to do things, assuming your attacker can't really forge voiceprints (and this seems hard, even for the NSA). From that point you can push strong public keys out to a dedicated text/email app. That we don't do this is not so much because it's a bad idea -- it's because so far people haven't tried it.

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