Re: [Int-area] Where/How is the features innovation, happening? Re: 202112221726.AYC

["Abraham Y. Chen" <[e-mail]>]

Hi, YiHao:

0)    I am glad that you distilled the complex and elusive privacy / 
security tradeoff issues to a very unique and concise perspective.

1)    Yes, the IPv4 CG-NAT and IPv6 Temporary address may seem to 
provide some privacy protection. However, with the availability of the 
computing power, these (and others such as VPN) approaches may be just 
ostrich mentality.  On the other hand, they provide the perfect excuse 
for the government (at least US) to justify for "mass surveillance". For 
example, the following is a recent news report which practically defeats 
all current "privacy protection" attempts.

https://www.usatoday.com/story/news/2021/12/08/federal-court-upholds-terrorism-conviction-mass-surveillance-case/6440325001/

2)    Rather than contradicting efforts, it is time to review whether 
any of these schemes such as mapping techniques really is effective for 
the perceived "protection". As much of the current science fiction type 
crime scene detective novel / movie / TV program hinted, the government 
probably has more capability to zero-in on anyone than an ordinary 
citizen can imagine, anyway. And, businesses have gathered more 
information about us than they will ever admit. Perhaps we should "think 
out of the box" by going back to the PSTN days of definitive subscriber 
identification systems, so that accordingly we will behave appropriately 
on the Internet, and the government will be allowed to only monitor 
suspected criminals by filing explicit (although in secret) requests, 
case by case, to the court for approval?


Happy Holidays!



Abe (2021-12-22 21:00 EST)


Hello Tom,

The privacy countermeasure for IPv4/IPv6 is interestingly different.
IPv4 usually utilize CGNAT, i.e., M(hosts)-to-N(IPs), where M >> N so that the host could remain anonymous
IPv6 usually utilize Temporary address, i.e., 1(host)-to-M(IPs[at least suffix level]), where M >> 1 so that the host could remain anonymous.

HOWEVER, I don't feel any approach reaches privacy perfectly, because access network have a global perspective on M-to-N or 1-to-M mapping.
For this, it is hard to be convinced that IPv4/6 itself can reach a perfect privacy.

Thanks,
Yihao Jia

-----------

I believe CGNAT is better than IPv6 in terms of privacy in addressing.
In fact one might argue that IPv4 provides better privacy and security
than IPv6 in this regard. Temporary addresses are not single use which
means the attacker can correlate addresses from a user between
unrelated flows during the quantum the temporary address is used. When
a user changes their address, the attacker can continue monitoring if
it is signaled that the address changed. Here is a fairly simple
exploit I derived to do that (from
draft-herbert-ipv6-prefix-address-privacy-00).

The exploit is:
       o An attacker creates an "always connected" app that provides some
         seemingly benign service and users download the app.
       o The app includes some sort of persistent identity. For instance,
         this could be an account login.
       o The backend server for the app logs the identity and IP address
         of a user each time they connect
       o When an address change happens, existing connections on the user
         device are disconnected. The app will receive a notification and
         immediately attempt to reconnect using the new source address.
       o The backend server will see the new connection and log the new
         IP address as being associated with the specific user. Thus,
the server has
         a real-time record of users and the IP address they are using.
       o The attacker intercepts packets at some point in the Internet.
         The addresses in the captured packets can be time correlated
         with the server database to deduce identities of parties in
         communications that are unrelated to the app.

The only way I see to mitigate this sort of surveillance is single use
addresses. That is effectively what  CGNAT can provide.

Tom


-- 
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus