Bitcoin Forum
December 11, 2016, 04:29:11 AM *
News: To be able to use the next phase of the beta forum software, please ensure that your email address is correct/functional.
 
   Home   Help Search Donate Login Register  
Pages: [1]
  Print  
Author Topic: Are bitcoin addresses a limited resource?  (Read 1618 times)
Piligrim
Newbie
*
Offline Offline

Activity: 13


View Profile
May 28, 2011, 06:16:32 AM
 #1

Every time there is a transaction an address is generated, and it remains valid. VISA network is said to be currently processing 2000 transactions per second. At this rate will the bitcoin addresses ever run out? Or start duplicating? Either way, I am just trying to find out if this is one of the system constraints. Thank you.
1481430551
Hero Member
*
Offline Offline

Posts: 1481430551

View Profile Personal Message (Offline)

Ignore
1481430551
Reply with quote  #2

1481430551
Report to moderator
1481430551
Hero Member
*
Offline Offline

Posts: 1481430551

View Profile Personal Message (Offline)

Ignore
1481430551
Reply with quote  #2

1481430551
Report to moderator
1481430551
Hero Member
*
Offline Offline

Posts: 1481430551

View Profile Personal Message (Offline)

Ignore
1481430551
Reply with quote  #2

1481430551
Report to moderator
Advertised sites are not endorsed by the Bitcoin Forum. They may be unsafe, untrustworthy, or illegal in your jurisdiction. Advertise here.
1481430551
Hero Member
*
Offline Offline

Posts: 1481430551

View Profile Personal Message (Offline)

Ignore
1481430551
Reply with quote  #2

1481430551
Report to moderator
theymos
Administrator
Legendary
*
expert
Offline Offline

Activity: 2506


View Profile
May 28, 2011, 06:50:55 AM
 #2

There are 2160 possible addresses, which is a ridiculous number. If every person on Earth makes ten addresses per second for 20 years (2x1018 total addresses), then the probability that at least two of these addresses collide is about 1.57x10-12.

1NXYoJ5xU91Jp83XfVMHwwTUyZFK64BoAD
markm
Legendary
*
Offline Offline

Activity: 1792



View Profile WWW
May 28, 2011, 07:22:38 AM
 #3

Possible domain names are actually even more numerous than possible bitcoin addresses, aren't they? Or about the same maybe?

So bitcoin addresses that actually print out as some cool intelligible string might well be as limited a resource as domain names, though discovering a private key giving you the actual use of such a possible address presents a challenge even more difficult than mining blocks.

-MarkM-

Browser-launched Crossfire client now online (select CrossCiv server for Galactic  Milieu)
Free website hosting with PHP, MySQL etc: http://hosting.knotwork.com/
norn
Newbie
*
Offline Offline

Activity: 28



View Profile
May 28, 2011, 08:58:56 AM
 #4

There are 2160 possible addresses, which is a ridiculous number. If every person on Earth makes ten addresses per second for 20 years (2x1018 total addresses), then the probability that at least two of these addresses collide is about 1.57x10-12.
There are a lot of address, it's true. But difficulty of generating one address is the same as calculating one hash. What if somebody starts to generate address using OpenCL with speed of 4 Ghashes? This guy can get 345600000000000 of addresses every day. 63072*1012 per year...

This is relatively slow, but remember - address is a limited resource. What if there are 1000000 people? What if in 10 years we can calculate 10 Thashes/sec easily?

Good talkers are not good doers.
theymos
Administrator
Legendary
*
expert
Offline Offline

Activity: 2506


View Profile
May 28, 2011, 09:05:25 AM
 #5

But difficulty of generating one address is the same as calculating one hash.

No: you also have to generate an ECDSA public key, or else the address is useless. Bitcoin also hashes the public key twice.

1NXYoJ5xU91Jp83XfVMHwwTUyZFK64BoAD
zef
Member
**
Offline Offline

Activity: 90


View Profile
May 28, 2011, 09:34:28 PM
 #6

Addresses are a 160 bit number(hashed from a hash of a public key), but only a fraction of those possibilities are well-formed, ie many numbers will never be reached by the hashing function. This means that the space of valid addresses is smaller than 2^160.  By how much, I don't know, but if you are doing calculations based on 2^160, those results are probably incorrect.

With that said, private keys are based on a 256 bit number, these are the numbers you would probably want to be generating to create key collisions. Much bigger search space, and even if not every number is a well formed address, you could lose 100 bits and still be extremely secure from what i've read, along the lines of what previous posters have said.

Please correct me if I'm wrong about any of this, I am not an expert by any means.
grue
Global Moderator
Legendary
*
Offline Offline

Activity: 1932



View Profile
May 28, 2011, 10:26:41 PM
 #7

There are 2160 possible addresses, which is a ridiculous number. If every person on Earth makes ten addresses per second for 20 years (2x1018 total addresses), then the probability that at least two of these addresses collide is about 1.57x10-12.
There are a lot of address, it's true. But difficulty of generating one address is the same as calculating one hash. What if somebody starts to generate address using OpenCL with speed of 4 Ghashes? This guy can get 345600000000000 of addresses every day. 63072*1012 per year...

This is relatively slow, but remember - address is a limited resource. What if there are 1000000 people? What if in 10 years we can calculate 10 Thashes/sec easily?

they'll make more money by mining.

It is pitch black. You are likely to be eaten by a grue.

Tired of annoying signature ads? Ad block for signatures
Piligrim
Newbie
*
Offline Offline

Activity: 13


View Profile
May 29, 2011, 02:30:02 AM
 #8

Quote
they'll make more money by mining.

This is not about money. This is about a potential flaw in bitcoin architecture that would allow one organization or entity to suppress it. And so far I am not convinced, because with the finite numbers it's just a matter of technology. How feasible is that? Well, we have to get our algebra straight.
theymos
Administrator
Legendary
*
expert
Offline Offline

Activity: 2506


View Profile
May 29, 2011, 02:47:11 AM
 #9

The size of addresses can easily be increased later on. No changes to the protocol would be required. For now 2160 seems plenty.

1NXYoJ5xU91Jp83XfVMHwwTUyZFK64BoAD
norn
Newbie
*
Offline Offline

Activity: 28



View Profile
May 29, 2011, 04:30:40 AM
 #10

The size of addresses can easily be increased later on. No changes to the protocol would be required. For now 2160 seems plenty.
good news then Smiley

Good talkers are not good doers.
Pages: [1]
  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!