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The idea I've proposed (although I'm sure I'm not the first to have done it) would leave most of TLS untouched. The only portion of the handshake and subsequent

The idea I've proposed (although I'm sure I'm not the first to have done it) would leave most of TLS untouched. The only portion of the handshake and subsequent steps which would be different is that which verifies the server's certificate. Everything else would be the same. My understanding of pinning is that it could just as well be used in a namecoin based system, and could enhance the security of that scheme just as it does with the CA scheme. All of these ideas could work together, with namecoin as the external, third-party source of trust instead of the CAs. So I guess a better title for the post would have been: "Namecoin, A Replacement For Certificate Authorities"

tptacek 13y ago
Once we have dynamic pinning, we don't need an elaborate distributed cryptographic ledger to solve this problem.
- deleted 13y ago
  [deleted]
- schoen 13y ago
  Maybe, but it could nonetheless help with the first-visit problem. There are at least three proposals with a distributed cryptographic ledger to reform or replace the CA system: Namecoin, Sovereign Keys, and Certificate Transparency. Each of them has some security benefit relative to TACK alone in the case of a user-agent's first visit to a site. In SK and CT the ledger is less distributed than a Bitcoin blockchain, although these systems have historical influence from discussions sparked by the existence of Bitcoin. Ben Laurie argues that proof of work is actually superfluous to the security model of these systems: http://www.links.org/files/decentralised-currencies.pdf http://www.links.org/files/decentralised-currencies.pdf http://www.links.org/files/distributed-currency.pdf http://www.links.org/files/distributed-currency.pdf Anyway, to refocus, a decentralized or distributed ledger does have the potential to help with the first-visit introduction problem, because you can have another place to turn for ground truth or at least for evidence that the certs you accept are publicly known. (There are also alternative techniques that don't rely on such a ledger, including Moxie's own Convergence.)
- read 13y ago
  When will we have dynamic pinning? I'm ready right now to try either TACK or crypt.io. What should I do if I want results over the next 24 hours? Also, and I mean this for both TACK and crypt.io, is there a self-contained, easy example someone can run and understand that shows if TACK and crypt.io work?
- InclinedPlane 13y ago
  A distributed system might make sense. Build an API (could be a REST system with some basic conventions) that allows sites to vouch for the certs of certain other sites. The advantage is that you can then poll several sites to check the validity of a certain cert instead of being reliant on a single point of failure. Alternately you could use arbitrary key signing which the original site presented up along with their cert. It certainly seems preferable to the single-point-of-failure systems we have now.
itistoday2 13y ago
The idea I've proposed (although I'm sure I'm not the first to have done it) I find your wording a bit strange here. Saying that you proposed the idea and yet half-acknowledging prior work, as if you're not aware of it. You and Marco were at my senior project presentation where I talked this very issue (several weeks ago). Half of your blog post came out of my talk. Happy to see you were able to figure out the last slide was partly referring to Namecoin.[1] This idea has also been discussed for some time on the Namecoin forums, and various security mailing lists and websites. I'm glad more people are exploring this option. It would be nice if they were a bit more polite. [1] http://cl.ly/image/153W3X3Q140y/Screen%20Shot%202013-11-23%20at%207.03.19%20PM.jpg http://cl.ly/image/153W3X3Q140y/Screen%20Shot%202013-11-23%2...

tptacek 13y ago

Once we have dynamic pinning, we don't need an elaborate distributed cryptographic ledger to solve this problem.

deleted 13y ago
[deleted]
schoen 13y ago
Maybe, but it could nonetheless help with the first-visit problem. There are at least three proposals with a distributed cryptographic ledger to reform or replace the CA system: Namecoin, Sovereign Keys, and Certificate Transparency. Each of them has some security benefit relative to TACK alone in the case of a user-agent's first visit to a site. In SK and CT the ledger is less distributed than a Bitcoin blockchain, although these systems have historical influence from discussions sparked by the existence of Bitcoin. Ben Laurie argues that proof of work is actually superfluous to the security model of these systems: http://www.links.org/files/decentralised-currencies.pdf http://www.links.org/files/decentralised-currencies.pdf http://www.links.org/files/distributed-currency.pdf http://www.links.org/files/distributed-currency.pdf Anyway, to refocus, a decentralized or distributed ledger does have the potential to help with the first-visit introduction problem, because you can have another place to turn for ground truth or at least for evidence that the certs you accept are publicly known. (There are also alternative techniques that don't rely on such a ledger, including Moxie's own Convergence.)
read 13y ago
When will we have dynamic pinning? I'm ready right now to try either TACK or crypt.io. What should I do if I want results over the next 24 hours? Also, and I mean this for both TACK and crypt.io, is there a self-contained, easy example someone can run and understand that shows if TACK and crypt.io work?
InclinedPlane 13y ago
A distributed system might make sense. Build an API (could be a REST system with some basic conventions) that allows sites to vouch for the certs of certain other sites. The advantage is that you can then poll several sites to check the validity of a certain cert instead of being reliant on a single point of failure. Alternately you could use arbitrary key signing which the original site presented up along with their cert. It certainly seems preferable to the single-point-of-failure systems we have now.

itistoday2 13y ago

The idea I've proposed (although I'm sure I'm not the first to have done it) I find your wording a bit strange here. Saying that you proposed the idea and yet half-acknowledging prior work, as if you're not aware of it. You and Marco were at my senior project presentation where I talked this very issue (several weeks ago). Half of your blog post came out of my talk. Happy to see you were able to figure out the last slide was partly referring to Namecoin.[1] This idea has also been discussed for some time on the Namecoin forums, and various security mailing lists and websites. I'm glad more people are exploring this option. It would be nice if they were a bit more polite. [1] http://cl.ly/image/153W3X3Q140y/Screen%20Shot%202013-11-23%20at%207.03.19%20PM.jpg http://cl.ly/image/153W3X3Q140y/Screen%20Shot%202013-11-23%2...