Bitcoin Forum
July 20, 2017, 08:46:50 PM *
News: The warning which may be displayed by Bitcoin Core about unknown versions is related to BIP91, and can be safely ignored.
 
   Home   Help Search Donate Login Register  
Pages: « 1 [2]  All
  Print  
Author Topic: possible to use up ALL wallet address combinations?  (Read 4111 times)
netrin
Sr. Member
****
Offline Offline

Activity: 322


FirstBits: 168Bc


View Profile
July 21, 2011, 03:14:24 AM
 #21

If every particle in the known universe could create a billion addresses a second for the entire age of the universe, they would generate about one-quintillionth of the possible addresses.

Sorry JoelKatz. I know you mean to say "It's highly unlikely" (TM), but you're way overestimating the address space which is numerous orders of magnitude LESS than the number of atoms in the universe (what I think you mean by particle), so if every atom generated just ONE address, the vast majority of them would be expected to collide with others. In fact, unique values would be exceedingly rare.

Is it possible that some individual on the planet has a unique birthday?

The size of the 160 bit SHA-1 key space is in the same order of magnitude as the number of atoms in the Earth (~10^50)

This estimate is accurate to about one order of magnitude. If every atom of the Earth generated ONE address, then the chance of collision approaches 100% and only about half of all addresses would be expected to be unique.

Greenlandic tupilak. Hand carved, traditional cursed bone figures. Sorry, polar bear, walrus and human remains not available for export.
1500583610
Hero Member
*
Offline Offline

Posts: 1500583610

View Profile Personal Message (Offline)

Ignore
1500583610
Reply with quote  #2

1500583610
Report to moderator
Advertised sites are not endorsed by the Bitcoin Forum. They may be unsafe, untrustworthy, or illegal in your jurisdiction. Advertise here.
JoelKatz
Legendary
*
Offline Offline

Activity: 1568


Democracy is vulnerable to a 51% attack.


View Profile WWW
July 21, 2011, 05:17:28 AM
 #22

If every particle in the known universe could create a billion addresses a second for the entire age of the universe, they would generate about one-quintillionth of the possible addresses.

Sorry JoelKatz. I know you mean to say "It's highly unlikely" (TM), but you're way overestimating the address space which is numerous orders of magnitude LESS than the number of atoms in the universe (what I think you mean by particle), so if every atom generated just ONE address, the vast majority of them would be expected to collide with others. In fact, unique values would be exceedingly rare.
Ack! You're right. I confused powers of 10 with powers of 2.

In any event, creating a 160-bit hash collision is vastly easier than anything that would constitute an attack on bitcoin, and nobody's even close to doing that yet. And even if they did, we'd just respond by using the full 256-bit public key.

I am an employee of Ripple. Follow me on Twitter @JoelKatz
1Joe1Katzci1rFcsr9HH7SLuHVnDy2aihZ BM-NBM3FRExVJSJJamV9ccgyWvQfratUHgN
netrin
Sr. Member
****
Offline Offline

Activity: 322


FirstBits: 168Bc


View Profile
July 21, 2011, 12:03:44 PM
 #23

In any event, creating a 160-bit hash collision is vastly easier than anything that would constitute an attack on bitcoin, and nobody's even close to doing that yet. And even if they did, we'd just respond by using the full 256-bit public key.

Right. It's telling that we are arguing about the number of atoms in the universe, etc. A collision is simply not something we should be worrying about before disruptive technology such as quantum computing or the invalidation of mathematical theories established before Christ (Euclid 300 BCE).

In order for brute forcing a collision to be more profitable than generating a block, then the current target divided by the number of money-holding addresses (10M?) must be less than one, but it's currently something like 1594393648759678455702984006915721031668773442824246741.




Greenlandic tupilak. Hand carved, traditional cursed bone figures. Sorry, polar bear, walrus and human remains not available for export.
Pages: « 1 [2]  All
  Print  
 
Jump to:  

Sponsored by , a Bitcoin-accepting VPN.
Powered by MySQL Powered by PHP Powered by SMF 1.1.19 | SMF © 2006-2009, Simple Machines Valid XHTML 1.0! Valid CSS!