clarify roger's alternatives on proposal 109

svn:r9810
This commit is contained in:
Roger Dingledine 2007-03-13 02:37:43 +00:00
parent bf3b3a44f3
commit b4bcd12709

View File

@ -22,7 +22,7 @@ Overview:
Motivation: Motivation:
Since it is possible for an attacker to register an arbitrarily large Since it is possible for an attacker to register an arbitrarily large
number of Tor routers, it is possible for malicious parties to do this to number of Tor routers, it is possible for malicious parties to do this
as part of a traffic analysis attack. as part of a traffic analysis attack.
Security implications: Security implications:
@ -32,7 +32,7 @@ Security implications:
Specification: Specification:
We propose that the directory servers check if an incoming Tor router IP We propose that the directory servers check if an incoming Tor router IP
address is already registered under another router. If this is the case, address is already registered under another router. If this is the case,
then prevent this router from joining the network. then prevent the new router from joining the network.
Compatibility: Compatibility:
@ -70,8 +70,13 @@ Alternatives:
Roger suggested that instead of capping number of servers per IP to 1, we Roger suggested that instead of capping number of servers per IP to 1, we
should cap total declared bandwidth per IP to some N, and total declared should cap total declared bandwidth per IP to some N, and total declared
servers to some M. (He suggested N=5MB/s and M=5.) servers to some M. (He suggested N=5MB/s and M=5.) Directory authorities
would then always choose to keep the highest-bandwidth running servers
-- if they pick based on time joining the network we can get into bad
race conditions.
Roger also suggested that rather than not listing servers, we mark them as Roger also suggested that rather than not listing servers, we mark them as
not Valid. not Running. (He originally suggested marking them as Running but not
Valid, but that would still allow an attacker to control an arbitrary
number of middle hops, which is still likely to be worrisome.)