Re: [cryptography] Math corrections

2011-09-22 Thread ianG
Hi Arshad, It occurs to me that we're almost there. On 22/09/11 02:30 AM, Arshad Noor wrote: Thirdly, lets assume that the compromised CA has *explicitly* entered into a cross-certification agreement with one or more other TTP CAs. Right, they got themselves listed by the browsers, who hid

Re: [cryptography] Math corrections

2011-09-21 Thread Arshad Noor
On 09/18/2011 11:59 AM, Peter Gutmann wrote: Arshad Noorarshad.n...@strongauth.com writes: Just because you come across one compromised CA out of 100 in the browser, does not imply that the remaining 99 are compromised (which is what you are implying with your statement). Since browser PKI

Re: [cryptography] Math corrections

2011-09-21 Thread Arshad Noor
On 09/18/2011 11:57 AM, Peter Gutmann wrote: Arshad Noorarshad.n...@strongauth.com writes: Are there weaknesses in PKI? Undoubtedly! But, there are failures in every ecosystem. The intelligent response to certificate manufacturing and distribution weaknesses is to improve the quality of

Re: [cryptography] Math corrections

2011-09-21 Thread Jeffrey Walton
On Wed, Sep 21, 2011 at 12:30 PM, Arshad Noor arshad.n...@strongauth.com wrote: On 09/18/2011 11:59 AM, Peter Gutmann wrote: Arshad Noorarshad.n...@strongauth.com  writes: Just because you come across one compromised CA out of 100 in the browser, does not imply that the remaining 99 are

Re: [cryptography] Math corrections

2011-09-21 Thread ianG
Hi all, On 22/09/11 02:30 AM, Arshad Noor wrote: On 09/18/2011 11:59 AM, Peter Gutmann wrote: Arshad Noorarshad.n...@strongauth.com writes: Just because you come across one compromised CA out of 100 in the browser, does not imply that the remaining 99 are compromised (which is what you are

Re: [cryptography] Math corrections

2011-09-21 Thread Chris Palmer
On Wed, Sep 21, 2011 at 11:30 AM, ianG i...@iang.org wrote: It's a good term!  Add my use:  There is a universal implicit cross-certification in the secure browsing PKI, and the industry knows it, or should know it. Indeed, we can show evidence of this in Chrome's CA pinning. I had assumed

Re: [cryptography] Math corrections

2011-09-20 Thread Jeffrey Walton
On Mon, Sep 19, 2011 at 7:31 PM, Benjamin Kreuter brk...@virginia.edu wrote: On 09/18/2011 05:11 PM, Marsh Ray wrote: B. If your threat model considers as an adversary government A, then you're in good company with governments B through Z. So all the comments on won't save you from The

Re: [cryptography] Math corrections

2011-09-19 Thread James A. Donald
Marsh Ray wrote: But the failure of *any* single CA allows a successful attack on *every* user connecting to *every* https website. On 2011-09-19 2:48 PM, Arshad Noor wrote: Would you care to explain this in more detail, Marsh? Please feel free to frame your explanation as if you were

Re: [cryptography] Math corrections

2011-09-19 Thread Marsh Ray
On 09/18/2011 11:48 PM, Arshad Noor wrote: On 09/18/2011 01:12 PM, Marsh Ray wrote: But the failure of *any* single CA allows a successful attack on *every* user connecting to *every* https website. Would you care to explain this in more detail, Marsh? Please feel free to frame your

Re: [cryptography] Math corrections

2011-09-19 Thread Peter Gutmann
James A. Donald jam...@echeque.com writes: The peers who do the peer reviewing for IDtrust, are not peers at all, but high priests who review for doctrinal conformity to the consensus of the the most holy synod, I know you meant that tongue-in-cheek, but in some cases it's frighteningly close

Re: [cryptography] Math corrections

2011-09-19 Thread Benjamin Kreuter
On 09/18/2011 05:11 PM, Marsh Ray wrote: B. If your threat model considers as an adversary government A, then you're in good company with governments B through Z. So all the comments on won't save you from The Government, while true, are also potentially writing off your biggest ally. Unless,

Re: [cryptography] Math corrections [was: Let's go back to the beginning on this]

2011-09-18 Thread James A. Donald
On 2011-09-18 3:37 PM, Marsh Ray wrote: Now you may be a law-and-order type fellow who believes that lawful intercept is a magnificent tool in the glorious war on whatever. But if so, you have to realize that on the global internet, your own systems are just as vulnerable to a lawfully executed

Re: [cryptography] Math corrections [was: Let's go back to the beginning on this]

2011-09-18 Thread Jeffrey Walton
On Sun, Sep 18, 2011 at 1:37 AM, Marsh Ray ma...@extendedsubset.com wrote: On 09/17/2011 11:59 PM, Arshad Noor wrote: The real problem, however, is not the number of signers or the length of the cert-chain; its the quality of the certificate manufacturing process. No, you have it exactly

Re: [cryptography] Math corrections [was: Let's go back to the beginning on this]

2011-09-18 Thread Ian G
On 18/09/11 2:59 PM, Arshad Noor wrote: On 09/17/2011 09:14 PM, Chris Palmer wrote: Thus, having more signers or longer certificate chains does not reduce the probability of failure; it gives attackers more chances to score a hit with (our agreed-upon hypothetical) 0.01 probability. After just

Re: [cryptography] Math corrections [was: Let's go back to the beginning on this]

2011-09-18 Thread Ian G
On 18/09/11 1:54 PM, Arshad Noor wrote: When one connects to a web-site, one does not trust all 500 CA's in one's browser simultaneously; one only trusts the CA's in that specific cert-chain. The probability of any specific CA from your trust-store being compromised does not change just because

Re: [cryptography] Math corrections

2011-09-18 Thread Arshad Noor
On 09/18/2011 03:05 AM, Ian G wrote: You guys have a very funny way of saying probability equals 100% but hey, ... as long as we get there in the end, who am I to argue :) That is not what I'm saying, Ian. Just because you come across one compromised CA out of 100 in the browser, does not

Re: [cryptography] Math corrections

2011-09-18 Thread Ralph Holz
Hi, Are there weaknesses in PKI? Undoubtedly! But, there are failures in every ecosystem. The intelligent response to certificate manufacturing and distribution weaknesses is to improve the quality of the ecosystem - not throw the baby out with the bath-water. And how do you propose to go

Re: [cryptography] Math corrections

2011-09-18 Thread Arshad Noor
On 09/18/2011 10:53 AM, Ralph Holz wrote: Hi, Are there weaknesses in PKI? Undoubtedly! But, there are failures in every ecosystem. The intelligent response to certificate manufacturing and distribution weaknesses is to improve the quality of the ecosystem - not throw the baby out with the

Re: [cryptography] Math corrections

2011-09-18 Thread Peter Gutmann
Arshad Noor arshad.n...@strongauth.com writes: Just because you come across one compromised CA out of 100 in the browser, does not imply that the remaining 99 are compromised (which is what you are implying with your statement). Since browser PKI uses universal implicit cross-certification, it

Re: [cryptography] Math corrections

2011-09-18 Thread Peter Gutmann
Arshad Noor arshad.n...@strongauth.com writes: Rather than shoot from the hip, the logical way to propose a solution would be to write a paper on it and submit it to IDTrust 2012 for discussion. If it is selected, it will have the merit of having been reviewed and deemed worthy of discussion.

Re: [cryptography] Math corrections

2011-09-18 Thread Ian G
On 19/09/11 3:50 AM, Arshad Noor wrote: On 09/17/2011 10:37 PM, Marsh Ray wrote: It really is the fact that there are hundreds of links in the chain and that the failure of any single weak link results in the failure of the system as a whole. I'm afraid we will remain in disagreement on

Re: [cryptography] Math corrections

2011-09-18 Thread Joe St Sauver
Ian asked: #Right -- how to fix the race to the bottom? Wasn't that supposed to be part of the Extended Validation solution? If it has failed at that, and I could see arguments either way, the other natural solution is probably government regulation. It likely wouldn't be pretty, but imagine:

Re: [cryptography] Math corrections

2011-09-18 Thread Marsh Ray
On 09/18/2011 12:50 PM, Arshad Noor wrote: On 09/17/2011 10:37 PM, Marsh Ray wrote: It really is the fact that there are hundreds of links in the chain and that the failure of any single weak link results in the failure of the system as a whole. I'm afraid we will remain in disagreement on

Re: [cryptography] Math corrections

2011-09-18 Thread James A. Donald
On 2011-09-19 3:50 AM, Arshad Noor wrote: I'm afraid we will remain in disagreement on this. I do not view the failure of a single CA as a failure of PKI, no more than I see the crash of a single airplane as an indictment of air-travel. And similarly, you do not see a wall with a single man

Re: [cryptography] Math corrections

2011-09-18 Thread James A. Donald
On 2011-09-19 4:21 AM, Arshad Noor wrote: Rather than shoot from the hip, the logical way to propose a solution would be to write a paper on it and submit it to IDTrust 2012 for discussion. Oh come on! Everyone is bored with IDtrust, which is why they have to keep changing their name. The

Re: [cryptography] Math corrections

2011-09-18 Thread James A. Donald
On 2011-09-19 5:30 AM, Joe St Sauver wrote: If it has failed at that, and I could see arguments either way, the other natural solution is probably government regulation. Many CAs are already government entities, and most are arguably quasi government entities - and by and large, the

Re: [cryptography] Math corrections

2011-09-18 Thread Ian G
On 19/09/11 7:11 AM, Marsh Ray wrote: Now that the cat's out of the bag about PKI in general and there's an Iranian guy issuing to himself certs for www.*.gov seemingly at will, Hmmm... did he do that? That would seem to get the message across to the PKI proponents far better than logic or

Re: [cryptography] Math corrections

2011-09-18 Thread Ian G
Hi Joe, On 19/09/11 5:30 AM, Joe St Sauver wrote: Ian asked: #Right -- how to fix the race to the bottom? Wasn't that supposed to be part of the Extended Validation solution? In a way, it was. More particularly it was the fix to certificate manufacturing. The obvious fix to low quality

Re: [cryptography] Math corrections

2011-09-18 Thread Arshad Noor
On 09/18/2011 03:33 PM, James A. Donald wrote: On 2011-09-19 3:50 AM, Arshad Noor wrote: I'm afraid we will remain in disagreement on this. I do not view the failure of a single CA as a failure of PKI, no more than I see the crash of a single airplane as an indictment of air-travel. And

Re: [cryptography] Math corrections

2011-09-18 Thread Arshad Noor
On 09/18/2011 01:12 PM, Marsh Ray wrote: But the failure of *any* single CA allows a successful attack on *every* user connecting to *every* https website. Would you care to explain this in more detail, Marsh? Please feel free to frame your explanation as if you were explaining this to a

[cryptography] Math corrections [was: Let's go back to the beginning on this]

2011-09-17 Thread Arshad Noor
Note: I've had to paraphrase some of the content from the archives, so please excuse me if this does not appear in the context of the original thread. I remember enough of my Advanced Statistics from school to know that the following line of reasoning is fallacious, and can leads to

Re: [cryptography] Math corrections [was: Let's go back to the beginning on this]

2011-09-17 Thread Arshad Noor
On 09/17/2011 09:14 PM, Chris Palmer wrote: Thus, having more signers or longer certificate chains does not reduce the probability of failure; it gives attackers more chances to score a hit with (our agreed-upon hypothetical) 0.01 probability. After just 100 chances, an attacker is all but

Re: [cryptography] Math corrections [was: Let's go back to the beginning on this]

2011-09-17 Thread Marsh Ray
On 09/17/2011 11:59 PM, Arshad Noor wrote: The real problem, however, is not the number of signers or the length of the cert-chain; its the quality of the certificate manufacturing process. No, you have it exactly backwards. It really is the fact that there are hundreds of links in the chain