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What's the matter with PGP?

blog.cryptographyengineering.com

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Re: What's the matter with PGP?

#121

Post by frabbit »

mike_hearn wrote: post #116
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…

Comodo give away free S/MIME certs: http://www.comodo.com/home/email-security/free-email-certifi... They can be generated and installed into the OS keystore by your browser automatically. By the low standards of crypto it works pretty well. Any old email client supports it out of the box.

Or, you can avoid the obvious problem in using a certificate generated by a non-trustable actor and use one which relies on the WoT instead: http://cacert.org

Re: What's the matter with PGP?

#122

Post by gecko »

sorbits wrote: post #107
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…

> […] with a very few exceptions (that probably prove the rule) Off topic and pedantic but exceptions do not prove rules. A specific exception like “you are allowed to do X when Y is true” may be used as proof of an (unwritten) rule about X being forbidden. I.e. here we use the exception (when Y is true we are allowed to do X) to prove that there is a general rule saying that X is forbidden.

That's also wrong. The expression uses an archaic transitive "prove," which means "to test." Thus, "the exception tests the rule," which makes more sense.

Re: What's the matter with PGP?

#123

Post by leni536 »

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.

"Hi, my email is john@doe.com and I'm johndoe on keybase.io" could work.

Re: What's the matter with PGP?

#124

Post by jimktrains2 »

Tomte wrote: post #98
jimktrains2 wrote: post #21

Earlier quoted context omitted.

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.

Now your collection of business cards is susceptible to tampering (no cryptographic authentication!). Do you never leave your collected business cards unattended at a conference or trade fair? Possible, if you put them into your shirt pocket. Do you store them in a vault lomg-term? Probably not. Is it impossible to impersonate you, either with a human sound-alike or by voice generation software? If you want perfect s…

I was imply it was a person-to-person handing of a business card and that if it wasn't then it could be handled via the phone (which you would need from something other than the business card). But, yes, I didn't explain that as well as I could have.

Re: What's the matter with PGP?

#125

Post by frabbit »

frabbit wrote: post #119
Tomte wrote: post #98

Earlier quoted context omitted.

Now your collection of business cards is susceptible to tampering (no cryptographic authentication!). Do you never leave your collected business cards unattended at a conference or trade fair? Possible, if you put them into your shirt pocket. Do you store them in a vault lomg-term? Probably not. Is it impossible to impersonate you, either with a human sound-alike or by voice generation software? If you want perfect s…

"Now your collection of business cards is susceptible to tampering (no cryptographic authentication!)." You are missing the part where it was suggested that the recipient of the business card telephones you and asks to verify the fingerprint.

In response to Tomte's criticism, this all boils down to the certification level http://tanguy.ortolo.eu/blog/article9/pgp-signature-infos 1) A fingerprint on a possibly compromised business card == 0 2) A fingerprint verified by phoning someone == 1 etc, And associated with that independently is of course the level of trust.

Sorry Tomte for not replying immediately to your message, but I've posted too much on this apparently.

Re: What's the matter with PGP?

#126

Post by beagle3 »

aianus wrote: post #113
beagle3 wrote: post #106

Earlier quoted context omitted.

If I understand correctly, namecoin is a distributed DNS replacement. Is there a way it addresses impersonation (e.g. MITM?), if so, can you please point me at documentation? DNS does not address it, and even DNSSEC does not (if you can forge the certificate, and you can mitm the traffic - which state actors are all capable of - then it doesn't matter that you can't forge the DNS response itself).

You can place your own self-signed public key in your namecoin record. There is no longer any need for certificate authorities which can be coerced into forging certificates.

Well, if this is properly supported by software using namecoin for DNS resolution, then - yes, this may work. The proof of the pudding, however, will arrive once it's eaten. I am not familiar with namecoin to point where the potential problems are, but do note that the failure of CAs is not in the cryptography but rather in the trust model. In modern cryptography, the problems are almost always with the practice, not with the theory.

Re: What's the matter with PGP?

#127

Post by lmm »

tptacek wrote: post #10
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…

An irreconcilable difference between you and I on this point: you think it's a good thing if people use bad crypto instead of no crypto, and I don't. I don't think bad crypto makes the global adversary go "aw, shit, we better target someone else". I think it makes them go "excellent, something else we can get a secret appropriation to go break".

Any crypto is about increasing the cost to attackers. There's no perfect crypto, and even if there were we would still have the $5 wrench attack. Security enhancing crypto is anything which is more expensive for the attacker than for the implementer, and I think encrypting with an unauthenticated key is firmly in that category.

Re: What's the matter with PGP?

#128

Post by rakoo »

beagle3 wrote: post #126
aianus wrote: post #113

Earlier quoted context omitted.

You can place your own self-signed public key in your namecoin record. There is no longer any need for certificate authorities which can be coerced into forging certificates.

Well, if this is properly supported by software using namecoin for DNS resolution, then - yes, this may work. The proof of the pudding, however, will arrive once it's eaten. I am not familiar with namecoin to point where the potential problems are, but do note that the failure of CAs is not in the cryptography but rather in the trust model. In modern cryptography, the problems are almost always with the practice, not…

> software using namecoin for DNS resolution

Actually, it should be the other way around: dnschain [0] bridges DNS resolution and namecoin, so there's no need to modify existing software.

[0] https://github.com/okTurtles/dnschain

Re: What's the matter with PGP?

#129

Post by driverdan »

godDLL wrote: post #99
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…

I can't drive. Not for lack of trying. I seemingly can't develop the the muscle memory of unintuitive (to me) concepts like "clockwise is right" and "counter-clockwise is left", nor can I get used to the way a gas pedal actuates non-linearly. These are just two examples of a long list of problems that I have with the controls. Then there is the utterly confusing signage. I just can't do any of it, not without sweatin…

If you can't figure out how to drive what do you do? You don't drive, you use an alternative. The same could be said for tech you can't learn.

Re: What's the matter with PGP?

#130

Post by mike_hearn »

frabbit wrote: post #121
mike_hearn wrote: post #116

Earlier quoted context omitted.

Comodo give away free S/MIME certs: http://www.comodo.com/home/email-security/free-email-certifi... They can be generated and installed into the OS keystore by your browser automatically. By the low standards of crypto it works pretty well. Any old email client supports it out of the box.

Or, you can avoid the obvious problem in using a certificate generated by a non-trustable actor and use one which relies on the WoT instead: http://cacert.org

I find WoT based solutions to be much less trustable overall.
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