I also learn something new every time I visit these forums.
For example, this interesting thread: https://bitcointalksearch.org/topic/m.13097839
Topic: Limited number of bitcoin addresses (Read 5284 times)
I thought there were as many possible addresses as possible private keys, is this not so?
Nope. Not so.
Bitcoin addresses are calculated with a RIPEMD160 hash. That's a 160 bit value. Therefore, there are only 2160 possible bitcoin addresses.
(Actually there are both P2PKH, starting with a "1", and P2SH addresses, starting with a "3", so that doubles the number of potential addresses to 2161)
That would make 2^256 or roughly 10^77 possible addresses.
2161 is approximately
2.9 X 1048 possible addresses.
10^77 possible bitcoin addresses, 10^80 atoms in the universe. So there are only 1000 times as many atoms in the universe as possible bitcoin addresses.
Nope.
Currently only 1048 possible bitcoin addresses. So there are 1032 times as many atoms in the universe as possible bitcoin addresses.
It's possible that additional bitcoin address types may be introduced in the future, but its impossible to predict just how many potential bitcoin addresses those future versions may enable.
The address space is unimaginably large, address collision is extremely unlikely. I understand that ever since I first know about bitcoin. But there is still a worrying thought in my mind that this is possible and there is no protection to my coins when that happens. I have got used to using bitcoin without this insecurity because I think if a collision happened, mine won't be the first to collide. 
i guess it is just another reason (although low on the list) for spreading out your bitcoins across multiple addresses. You must be joking. I hope you are joking. This is a joke, right?
must be joking, i hope he is joking.... but sadly i do not think he is joking 
The address space is unimaginably large, address collision is extremely unlikely. I understand that ever since I first know about bitcoin. But there is still a worrying thought in my mind that this is possible and there is no protection to my coins when that happens. I have got used to using bitcoin without this insecurity because I think if a collision happened, mine won't be the first to collide.
it'll take millions of years to have address collisions, so many possibilities
The number of base pairs in a human genome is about 3 billion base pairs. (10^12)
The bitcoin address search space is 2^160 (10^48)
Think about the scale of that. You are not able to count to 10^48 in your lifetime, let alone generate all bitcoin addresses.
At the time when all bitcoin addresses are collected, we are long dead.
The bitcoin address search space is 2^160 (10^48)
Think about the scale of that. You are not able to count to 10^48 in your lifetime, let alone generate all bitcoin addresses.
At the time when all bitcoin addresses are collected, we are long dead.
that 2^160 possible addresses is too big to fathom...but I kind of can get my head around the fact that we basically will never run out of addresses, but being truly random....it is possible for addresses to collide...although infinitesimal, yes?
and I guess the probability of that address either holding any or any significant amount of btc is even more infinitesimal?
but those possibilities exist?
and I guess the probability of that address either holding any or any significant amount of btc is even more infinitesimal?
but those possibilities exist?
I also do not beleive that this will happen any time soon. Once we are down to the last few hundred million addresses, I am sure they will find some way to recycle them or make it able to sell the addresses from one individual to another. Just a thought.
The universe is estimated to be 14 billion years. Lets say it will be there for another 50 billion years. If you want to exhaust 2^160 addresses, you and every other person on this planet must generate 100 million addresses every picosecond (a trillionth second) until the end of the universe. And to say what was already said in this thread in other words: once there is enough computing power on this planet to generate all bitcoin addresses, then the current bitcoin address scheme is broken and we need longer addresses.
You can't sell addresses
The address is generated from a private key that you choose at random. You don't want to use an address where someone else generated the private key and has full access to the account.
I also do not beleive that this will happen any time soon. Once we are down to the last few hundred million addresses, I am sure they will find some way to recycle them or make it able to sell the addresses from one individual to another. Just a thought.
This topic has nothing whatsoever to do with calculus. If you meant 'math class', say 'math class'.
While I'm at it, the distribution of particles in a gas has nothing whatsoever to do with the many-worlds interpretation of quantum mechanics, nor in fact with quantum mechanics itself. The old trope of all the gas suddenly coalescing on the left-hand side of the box is a *statistical* phenomenon, not a quantum one.
While I'm at it, the distribution of particles in a gas has nothing whatsoever to do with the many-worlds interpretation of quantum mechanics, nor in fact with quantum mechanics itself. The old trope of all the gas suddenly coalescing on the left-hand side of the box is a *statistical* phenomenon, not a quantum one.
This really isn't a problem and this kind of question would only be asked by somebody who did not take a calculus course in high school. Satoshi probably had this in mind when developing the protocol and as pointed out above, it is mathematically impossible to run out of addresses. Don't worry about it. The developers already thought about it.
We have been taught since childhood that numbers don't end anywhere, they go on till infinity. So, mathematically it's impossible for numbers to get end. So, is in the case of wallet addresses.. And wallet address comprises of alphabets too , so it's currently in near future tough for them to get finished.
But, even though it happens in future, simple solution is increasing or decreasing number of digits. But, currently it's not a matter to really think upon.
But, even though it happens in future, simple solution is increasing or decreasing number of digits. But, currently it's not a matter to really think upon.
There seems to be some confusion since you are looking at the encoded version of the Bitcoin address.
There are exactly 2160 possible addresses as long as we keep using RIPE-MD160.
2160 is 1,461,501,637,330,902,918,203,684,832,716,283,019,655,932,542,976.
We don't have to guess at this by looking at the ASCII encoded values (the human readable form you are seeing).
Do you often worry that someday all of the oxygen molecules in the room you are in will spontaneously drift away from the part of the room you are in and you would die? After all, that could happen, right? It is not impossible, right?
That should be a bigger worry for you than running out of Bitcoin addresses.
There are exactly 2160 possible addresses as long as we keep using RIPE-MD160.
2160 is 1,461,501,637,330,902,918,203,684,832,716,283,019,655,932,542,976.
We don't have to guess at this by looking at the ASCII encoded values (the human readable form you are seeing).
Do you often worry that someday all of the oxygen molecules in the room you are in will spontaneously drift away from the part of the room you are in and you would die? After all, that could happen, right? It is not impossible, right?
That should be a bigger worry for you than running out of Bitcoin addresses.
I am wondering where you go tthe 2 from in that equation
An 160 bit number is a sequences of 160 binary digits, expressed as a base 2 number. The 2 comes from the fact that base 2 is the type of number system what's being used. In the mathematics of permutations and combinations, you resolve the number of combinations by taking the number of possibilities in a given position as the mantissa, and the number of positions as the exponent.
Hence, the number of possible combinations given a set of base 2 numbers with 160 positions is 2160.
Nice graph at that site.
Check how impossible it is "for now".
http://www.toxigon.com/brute-forcing-bitcoin-brainwallet/
http://www.toxigon.com/brute-forcing-bitcoin-brainwallet/
one quindecillion, four hundred sixty-one quattuordecillion, five hundred one tredecillion, six hundred thirty-seven duodecillion, three hundred thirty undecillion, nine hundred two decillion, nine hundred eighteen nonillion, two hundred three octillion, six hundred eighty-four septillion, eight hundred thirty-two sextillion, seven hundred sixteen quintillion, two hundred eighty-three quadrillion, nineteen trillion, six hundred fifty-five billion, nine hundred thirty-two million, five hundred forty-two thousand, nine hundred seventy-six
This many...
This many...
With that nubmer of addresses. My computer would give a prgram running (if it was the only program running that had a higher priority). It would take 463,439,129,036,942.83301740386628494 years running at 2Gh/s
I imagine BurtW was assuming the many worlds interpretation of quantum mechanics (look up "quantum tunnelling" for more). Under this interpretation, the conception of air as a collection of particles bumping into one another is only an approximation to the truth.
No, BurtW's analogy works fine under the conception of air as a collection of particles randomly bumping into one another, and I've used the same analogy many times.
Under the conception of air as a collection of particles bumping into one another, the molecules are effectively moving around randomly. At any given moment in time, ANY arrangement of those molecules in a given space in has equal probability. There are MANY such arrangements that involve enough air to be in the immediate proximity of the air holes in your face. There are very few such arrangements that involve insufficient air to be in the immediate proximity of the air holes in your face. Is there any thing magical about your face that forces enough air to move to that location? Or are you simply counting on the extremely high probability that the few random arrangements that could kill you will never happen?
Ah yes, good point. I missed that.
Damn. I'm suddenly very conscious of my breathing. If I don't sleep well tonight I'm blaming you.
Jump to: