[Cryptography] BitCoin Question - This may not be the best place to ask

[Robert Christian]

Exactly my point.  What's the collision resolution strategy and why isn't
this a scary proposition?

On Sunday, December 22, 2013, Steve Weis wrote:

> On Sun, Dec 22, 2013 at 4:30 PM, Robert Christian
> <robertjchristian at gmail.com <javascript:;>> wrote:
> > 2) I am pointing out that addresses are finite, and 34 chars long... They
> > can only be upper or lower case, or 0..9.  So at the end of the day,
> after
> > all the fancy stuff, the number of all possible bitcoin addresses is
> > (26*2+10)^34 possible unique ids.
> >
> > So the number of possible unique addresses is actually relatively smalll.
> > Right?
>
> The address has 20-bytes of hash, a network ID byte prefix, and a
> 4-byte checksum. So, there are 2^160 possible unique addresses. This
> is converted into a 34 character base-58 string.
>
> You do bring up one point that many key pairs will collide for a
> particular address. That's why the hash function must be assumed to be
> collision resistant.
>
> As for when we might see collisions, with a birthday attack you'd
> expect there to be a 50% chance of some collision existing when there
> are roughly 2^80 addresses.
>
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