SSL fro hidden services

loki tiwaz loki_tiwaz at hotmail.com
Thu Oct 20 22:57:24 UTC 2005


hi,

>>>>That said, the certificate naming scheme may be way off, since there's 
>>>>no concept of a valid certificate (I doubt verisign will want to sign 
>>>>one for 786237261871621.onion :)

i am considering running an onion-based CA which could be used... i simply 
need to make a script which allows a user to sign a certificate signing 
request and produce a signed server key. the server key only needs to have 
its onion address as content, nothing more is required, and a link to import 
the CA key into the browser so that it can be trusted automatically by the 
browser.

>>>>However, assuming the user installs your self-signed cert, it *should* 
>>>>work the same unless there's something I'm missing.)
>>>>
>>>>Of course, you're really just protecting content from being sniffed 
>>>>between the user and the entry node (usually, the same machine, but not 
>>>>always), and the exit node and the hidden service (presumably, you 
>>>>control both).
>>>>
>>>>This is my understanding of it -- if someone has a better one please 
>>>>step on me without hesitation :)

yes, this is the case, and it is a valid reason to use ssl. in my opinion, 
since tor already uses multi-layered encryption anyway, one more layer at 
the core is not going to create that much of an extra load on the server, 
and it means that there is no way the traffic can be sniffed at any point - 
for example a trojan could sniff localhost traffic. also, using onion 
routing defeats the one way in which SSL can be attacked, by 
man-in-the-middle intermediaries on the network pathway, which of course 
cannot be known within the tor network. Also, it should be noted that tor 
exit nodes could potentially be modified to become men-in-the-middle, 
although this would not be possible without compromising the key of the 
server being contacted - another aspect of the advantage of using tor.

onion addresses are impossible to remember though - which brings me to 
another idea - of a name resolution system within the tor network so simpler 
names can be used. this would require a second directory system, i don't 
know if it is practical or not, but i thought i should put the idea out 
there because i2p has name resolution systems, and benig able to type in 
oniondomainname.onion rather than u15syoa125au.onion would be nice. it would 
increase the rate of take-up of hidden services, both use and hosting.

onion domains could be propagated throughout the onion network, so that 
every tor node can translate a name into an onion hashed address. there 
would also need to be a system to prevent name spoofing... how to ensure 
there is no collisions of names would be tricky - very likely it would 
require a set of authoritative name servers similar to how there is 
authoritative onion directory servers.

ah dammit, i am always ideas ideas ideas and so little action... 
prioritising goals is something i find difficult... i think i should make 
this idea a priority, however, which means joining the dev effort and, at 
the very least, defining a protocol, if not implementing code... well, 
anyway, i have put the idea out now. i think that the idea is a good one. 
tor is coming of age now and ideally tor should aim to provide all of the 
features one would expect in an internet layer, but with the guiding 
principle of protecting anonymity always ascendant. an onion-based CA would 
work much better if the name-resolution system were in place, so i think it 
should be the priority.

loki

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