Re: Address privacy

[Fernando Gont <[e-mail]>]

On 28/1/20 19:45, Tom Herbert wrote:
[...]
>> I don't think you can quantify privacy. What would be the units for that?
>>
>> There's secrecy and not-secrecy. But with these things, you simply
>> mitigate (to some extent) the ability to correlate network activity.
>>
> Fernando,
> 
> In the case of single use addresses, that is each flow gets its own
> addresses, the privacy effects are quantifiable. Since each flow has a
> different source address, no two flows or communications can be
> correlated to being sourced from the same user. In this case, the
> identifiers are not reused is used in multiple contexts, so it isn't
> possible to correlate seemingly unrelated activity using an
> identifier. When an identifier is reused for the same node, even once,
> then the possibility of correlations exists.

You are not quantifying privacy: that's still qualitative description.




>>> One might compare this to the policy of some sys admins that users need
>>> to change passwords regularly. The rationale is similar, but that
>>> practice has been most debunked as not improving security and in fact is
>>> more of a burden to users that providing any real value.
>>
>> I don't think it has been debunked. Certainly, if you change your
>> password, you limit the ability of the attacker that had obtained your
>> password from re-using the same credentials. (assuming they are not used
>> for a system where they can install backdoors, etc.). Most things we
>> emply for security have an associated lifetime...
>>
> It's a false sense of security. Here's a good analysis:
> https://www.ftc.gov/news-events/blogs/techftc/2016/03/time-rethink-mandatory-password-changes

Forcing password changes exacerbate some human aspects, and at times 
leads to trouble. That doesn't say it doesn't have a place.

Folks also argue that firewalls are a false sense of security. Some 
argue the same about resistance to address-scan -- even when the #1 task 
to hack a system is normally to find it. IMO, whatever makes the 
attacker's life harder has a place and a use.

Thanks,
-- 
Fernando Gont
SI6 Networks
e-mail: [e-mail]
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