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What's the matter with PGP?

blog.cryptographyengineering.com

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Re: What's the matter with PGP?

#81

Post by Spooky23 »

unimpressive wrote: post #12
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…

>They do indeed have an advantage in deployability! Deployability is worth more than might be immediately obvious. The question of deployment is directly related to the business of availability . If 99% of people used a crypto system that provided no real security beyond thwarting a global adversary, which also had the option for further measures to confirm identity when necessary, we would be in a much better positi…

You educate them.

The way I did this in a past life:

- Explain that email is a postcard. - Give examples of information that should not belong in email. - Provide demonstration of the issues people creates for themselves by breaking the rules. - provide tools to accomplish business needs (file transfer in particular) - Tell them that their email is subject to audit. - Implement technical controls to warn/enforce suspect behavior.

People want to do the right thing, but you must set clear expectations so they know what to do! The most secure email is one that is never sent.

Re: What's the matter with PGP?

#82

Post by dsr_ »

nktr1 wrote: post #57
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…

Just an idea that might not be very practical but what if there was X number of "master" public keys managed by trusted groups that could be used to verify other public keys and they were posted in plain text on billboards across towns (maybe could replace CAs?)... just like you can use the Debian keys to verify the Tails OS key..

If it became at all popular, some people would have to know the private key half (or be able to decrypt it for use, same thing)... and those people would be subject to bribery, coercion, and rubber-hose cryptanalysis. I would not want to be one of them; I have relatives whom I love.

Re: What's the matter with PGP?

#83

Post by mdavidn »

alaaibrahim wrote: post #80

> Now let's ignore the fact that you've just leaked your key request to an untrusted server via HTTP. This is a public Key, so secrecy it's not needed here, also he is providing the Fingerprint on another location, so if there was a MITM attack, it should happen on both twitter (HTTPS) and pgp.mit.edu

I think Matthew Green's point was more that requesting a public key leaks your intent to communicate with someone—the metadata, if you will—to an untrusted third-party.

Of course, e-mail headers, including From and To, must necessarily transit as cleartext, even when e-mail bodies are protected by PGP. The keyserver should perhaps be the least of Matthew's concern.

Re: What's the matter with PGP?

#84

Post by marcosdumay »

tptacek wrote: post #15
nodata wrote: post #14

Earlier quoted context omitted.

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.

Yes. DNSSEC. Because what we need is a trusted arbiter, and who better to fulfill that role than the governments of the US, or whatever country happens to own the TLD I use?

Well, it's at least better than X500. With DNSSEC you only have to trust one government, not all of them.

And you can also get more than one domain, in more than one TLD. Not very practical for automatic verification, but for surviving a manual verification several governments would have to collude against you.

I still think that there must be something better. But I'm probably not good enough to create it.

Re: What's the matter with PGP?

#85

Post by BillFranklin »

I think https://lavaboom.com/en/ addresses most of the issues mentioned. Just because pushing for privacy (an abstract idea, difficult to measure the worth of - especially on the Internet) is hard doesn't mean we shouldn't do it. Encryption is one of the fews things we can rely on and we should be using it. PGP isn't a lost cause, we just need to make it easy use - this includes automating (to some degree) the key exchange. /I'm one of the founders of Lavaboom, happy to answer any questions/

Re: What's the matter with PGP?

#86

Post by marcosdumay »

TeMPOraL wrote: post #68
Someone1234 wrote: post #49

Earlier quoted context omitted.

Counter example: I'm not too lazy to use HTTPS. Maybe if email encryption was more like HTTPS more people would use it? Just transparent and easy.

> Maybe if email encryption was more like HTTPS more people would use it? Just transparent and easy. Sure, but the point of a lot of comments here seems to be that It Can't Be Done.

It certainly can be done.

It's just that lots of people think HTTPS security is not good enough. (And you can include me on that set.)

Re: What's the matter with PGP?

#87

Post by croikle »

moreati wrote: post #60
tptacek wrote: post #18

Earlier quoted context omitted.

I'm baffled by that attitude (and CT, as well). So, you found out after the fact that the global adversary injected themselves in the middle of your conversation with a source. What do you do now? Move to an apartment in Russia? Also the things that break transparently-keyed systems do so repeatedly . That's what transparent keying means: it's mediated by machines, and factored the slow, clumsy, human interactions ou…

What is CT in this context?

I believe it's Certificate Transparency, a Google project for globally monitoring SSL certificates.

http://www.certificate-transparency.org/

Re: What's the matter with PGP?

#88

Post by croikle »

zimbatm wrote: post #67

> Except maybe not: if you happen to do this with GnuPG 2.0.18 -- one version off from the very latest GnuPG -- the client won't actually bother to check the fingerprint of the received key. Even in it's long form, it's relatively easy to generate different keys that have the same fingerprint.

I'm aware of simple brute-force attacks on short key IDs [0], which are just the last 32 bits of the fingerprint (e.g. 438CF0E2). With significant effort, one might be able to extend that to 64 bits.

I'd be much more surprised by a full fingerprint match. Wouldn't that imply a SHA-1 collision?

[0] http://www.asheesh.org/note/debian/short-key-ids-are-bad-new...

Re: What's the matter with PGP?

#89

Post by idlewords »

Tharkun wrote: post #66

Learning to drive a car is hard. You have to watch the road, coordinate hands and feet, anticipate other drivers' moves and so on. No one bats an eye about this, because "it's a skill you have to learn". If you don't play by the rules of the road, you'll end up killing someone, or getting killed. But for some reason (maybe because it's generally less life-threatening), people seem to expect deeply complex subjects, l…

The analogy to learning to drive is flawed, because we learn to drive with muscle memory, and our intuitions about the physical world serve use well when driving.

Neither of these obtains with cryptography. Mistakes are not obvious and you have to concentrate to get it right.

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