New Technology to Make Digital Data Disappear, on Purpose

Jerry Leichter leichter at
Wed Jul 22 20:30:45 EDT 2009

On Jul 21, 2009, at 10:48 PM, Perry E. Metzger wrote:

> dan at writes:
>>> The pieces of the key, small numbers, tend to =93erode=94 over  
>>> time as
>>> they gradually fall out of use. To make keys erode, or timeout,  
>>> Vanish
>>> takes advantage of the structure of a peer-to-peer file system. Such
>>> networks are based on millions of personal computers whose Internet
>>> addresses change as they come and go from the network.
>> One would imagine that as IPv6 rolls out, the need
>> for DHCP goes to zero excepting for mobile devices
>> attaching to public (not carrier) nets.  Yes?
> Off topic, but actually DHCP is still needed. A machine needs to
> configure a lot more than just its address and router in common cases
> (it wants things like DNS servers, NTP servers, etc.) and in large
> deployments, it is often far easier to let machines autoconfigure  
> these
> things during boot using DHCP even on comparatively hard wired
> networks.
> And with that, lets return to crypto...
The proposal makes use of an incidental property of existing DHT  
implementations:  Because many nodes are running on machines with  
dynamic IP addresses, rehashes - which cause the table to change and  
this leads to the loss of bits.  It's not actually clear from the  
paper how much of the bit loss is actually due to IP address changes  
and how much to other phenomena.  In any case, if this idea catches on  
and there isn't enough "noise" in the network naturally to give an  
adequate bit drop rate, it would be reasonable to add an explicit bit- 
dropping mechanism to some new release.  You'd need one to add IPv6  
support anyway!
                                                         -- Jerry

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