[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 erroneou

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

2011-09-17 Thread Chris Palmer
On Sep 17, 2011, at 8:54 PM, Arshad Noor wrote: > When one connects to a web-site, one does not trust all 500 CA's in > one's browser simultaneously; Actually, that is exactly the situation. If, and only if, the person operating the browser inspects the certificate chain and knows what to expec

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 ce

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 chai

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 execute

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 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 backwards. > >

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