Bitcoin Forum

So as far as I know that there are 2^160 or 1,461,501,637,330,902,918,203,684,832,716,283,019,655,932,542,976 addresses that can exist as long as the current algorithms continue to be used.  My question is how many bitcoin addresses have been generated to date and where can I find the number of addresses in use on the network?  (yes, the block chain but has someone extrapolated the information) Also how could we know or maybe estimate how many addresses have been generated offline (paper wallets, vanity addresses etc.)  As bitcoin adoption becomes more widespread at what point would this algorithm consider being changed? (I realize this may not occur for a very long time)

That's a huge number there. Perhaps you don't realize how huge it is.

Right now, Bitcoin can handle 7 transactions a second, but let's make that 1,000,000,000 transactions per second. And let's say that everybody uses a new address for every transaction. In this case, 31,557,600,000,000,000 new addresses would be used every year. Now, we want the chances of generating a duplicate address to be very small. Let's assume the highest acceptable risk is 1/1,000,000,000,000,000,000,000,000. With these parameters, it means that it will be another 4,631,219,222,408,874 years before there is a danger of a collision.

To put that number in perspective, there are 2^63 grains of sand on all the beaches of the world. This always gave me pause regarding bitcoins till i  realized just how big of a number 2^160 is. Even if you did collide with an address, whats the chance that it will actually be active and just not used but valueless. Does anyone know how many active addresses their are? It would be fun to put this in relation to a real world situation anyone can grasp.

wow

All you can do is make a pool asking this question, you cant known what program created particular Bitcoin address.

But number of vanity adresses could be estimated quite well.

Some black holes will evaporate before a collision is made.

This is a lot of time.

 :o

Would the address ran out if the whole world use it? I always though its unlimited until I read this topic...

This means you are 2.3 trillion times more likely to be killed by an asteroid than you are to encounter a similar bitcoin address, even at this hypothetically absurdly large number of transactions per second.  I'm not sure how to relate the actual current likelyhood but its like a couple hundred million times that 2.3 trillion?  lol.

So yea.........

That is so wrong I don't know where to point you to. For each new address there is a "danger" of collision, and that is it. Obviously, if you generate all the possible addresses, the next one is a collision for sure, there is no danger there as it is a guarantee.

Not going to happen. But isn't there a factor of luck? Even if it is estimated to happen in x years, can't it happen today? For example, when I was generating  vanity address, it said 3 days but after an hour it finished,

That's why I wrote, "Let's assume the highest acceptable risk is 1/1,000,000,000,000,000,000,000,000." By "danger", I meant a risk greater than 1/1,000,000,000,000,000,000,000,000. In reality, that risk is too high, but I got tired of counting 0s, and the purpose of the scenario is to make a point and not to prove something.

Well, if there is one oxygen molecule on the room, there is 50% change that it is not on your side of the room. If there is 2 molecules on the room, the change is 25% And so on.. do you realize, there is a danger than *all* the oxygen is on the *other side* of the room you are just now in?

lol.


You can find such info in this thread (first graph in the OP).
https://bitcointalk.org/index.php?topic=394221.0