Hi, Here are two issues with X509 that were hindrances for a solution like foaf+ssl to be deployed, but which can and are being fixed: 1. Client Side Certificate selection ------------------------------------ Browsers currently do a very bad job of allowing the user to choose his certificate (Safari being the absolute worse). As a result I posted "Firefox Hackers Needed" http://bit.ly/cQ5f48 earlier this week. @snej who is working at Google put up a picture of a solution for this in Chrome using a foaf+ssl certificate created by http://webid.myxwiki.org/ http://bit.ly/azCXTU Vote for it! 2. Server side certificates --------------------------- One factor that people mention often with foaf+ssl is that the server has to have his own certificate. This means registration with a CA which is costly and tedious and it does not really solve the problems of server authentication as Dan Kaminsky shows ruthlessly in "Black Ops of PKI" http://bit.ly/4Uwb2K . To summarise his talk, server security is in a double bind: 1- Dan Kaminsky's DNS poisoning attack which is very well explained by Rick Van Rein's presentation "Cracking Internet: the urgency of DNSSEC" ( http://bit.ly/2darr8 view with FFox > 3.5 as it uses ogg video) means that a DNS easily be hacked in 6 weeks, and a lot of money poured into the wrong people's pockets. So there is a financial incentive to break DNS. 2. The solution of using https with X.509 public key cryptography's backing cannot work because there is a race to the bottom in the way CA's issue certificates. For enough money it is not that difficult to become God and to pretend you are anyone. Given the above DNSsec has become urgent enough, that it is being deployed. - verisign will put .com in July http://bit.ly/dyd54E - .org will be available in June http://bit.ly/abEJ28 - .gov went dnssec in March 2009 http://bit.ly/bH27b0 - The root will be signed July 2010 http://bit.ly/9YQMDJ - a map of dnssec deployment http://www.xelerance.com/dnssec/ So listening to Dan Kaminsky you would think that he is against X509. Well certainly it could be improved a lot, but he is not quite as negative as one may think. X.509 with DNSsec seems to be something he thinks can work. What he told me after his CCC and HAR talks and what you can see in the last few minutes of the HAR talk "X509 considered Harmful" http://bit.ly/2darr8 is that once DNS is secure one could put the X509 (self signed even) certs into the DNS records. This would bypass the need for CAs. [ I hope I understood him correctly ]. I am not sure what needs to be done to make this possible with the browser vendors, but it would massively improve security on the web. As a result I have fait that the global situation on the internet will only make foaf+ssl solutions easier and more secure to deploy, enabling a completely distributed social network to emerge, free and without the spying, as Eben Moglen author of the GPL said so well recently http://bit.ly/brQmJz Henry Social Web Architect http://bblfish.net/ Social Web Architect http://bblfish.net/