Re: [dnsext] Privacy in IP address indication (Was: I-D ACTION:draft-vandergaast-edns-client-ip-00.txt

[Eric Brunner-Williams <[e-mail]>]

in 8, there is a repetition of the choice (mistake in my opinion) that 
truncating a 32bit address to 24bits provided "privacy".

there are two issues.

first, what data is being collected by the server, independent of any 
assertions of preference by the address provisioning client?

i'm not suggesting that the server should signal the client what its 
data collection practices are, but it is a possibility, this is what 
the w3c's p3p work has made possible, and there is a dcp element (data 
collection policy) in epp.

the mistake made in the p3p spec group was to pick 24bits as providing 
"privacy". this choice was made without reference to the structure of 
any particular address allocation in which an address for which some 
"privacy" was desired, or to the temporal properties of addresses in 
the smallest block to which that address belong.

in short, for the purposes of geo-mumble, a purpose this draft appears 
to share, no use was made of information that may be sufficient to 
identify the geo property sufficient for the proposed service, e.g., 
is this user on mars, for some value of mars, and, there was no 
awareness that dynamically provisioned 32bit identifiers are "static" 
of significant periods of time, and other correlative tools are 
available for user profiling business (and non-business) models which 
have access to "masked" data and other sources of data.

second, there is the utility of the client, the address bits 
provisioning source, asserting what the provisioned bits are.

this draft appears to comingle locality, which may be useful, and the 
frequently repeated "privacy toggle" semantics, which ignores the 
richer semantics of discovering the policy of the address bits 
collector, which should discard these bits as soon as the localized 
service is accomplished, but could keep them indefinitely, and 
corrolate them with other data sources (see "doubleclick" generally).

eric