Bitcoin Forum

Bitcoin => Bitcoin Discussion => Topic started by: spacecaptain on November 27, 2013, 04:31:28 PM



Title: Randomly Finding Private Keys in Use
Post by: spacecaptain on November 27, 2013, 04:31:28 PM
For a long time it troubled me that someone could simply "get lucky" and generate an address with the same private key as mine. I knew the odds... but stil...

This article gives an awesome explanation of how this Works and I thought I could share with you guys:
http://www.miguelmoreno.net/bitcoin-address-collision/


Title: Re: Randomly Finding Private Keys in Use
Post by: anti-scam on November 27, 2013, 05:14:44 PM
Even better, you can keep your money in multiple addresses to make the already astronomically low probability even lower.


Title: Re: Randomly Finding Private Keys in Use
Post by: PenAndPaper on November 27, 2013, 05:17:05 PM
For a long time it troubled me that someone could simply "get lucky" and generate an address with the same private key as mine. I knew the odds... but stil...

If you say "but still" it means that you don't know the odds.


Title: Re: Randomly Finding Private Keys in Use
Post by: spacecaptain on November 27, 2013, 05:23:14 PM
For a long time it troubled me that someone could simply "get lucky" and generate an address with the same private key as mine. I knew the odds... but stil...

If you say "but still" it means that you don't know the odds.

Well, we all know that it is almost impossible. The troubling part here is the "almost".

But I do agree with anti-scam... dividing your funds in multiple wallets is a safe bet.


Title: Re: Randomly Finding Private Keys in Use
Post by: TomHirsch on November 27, 2013, 05:34:31 PM
Well, we all know that it is almost impossible. The troubling part here is the "almost".
These are the same people who believe they can win the lottery - 35 times in a row.


Title: Re: Randomly Finding Private Keys in Use
Post by: TTBit on November 27, 2013, 06:09:38 PM

Ranking game: Please rank from most likely to least likely.

1) Barry Bonds type player hitting 250 home-runs in 664 Plate Appearances (He hit 73 in 664 PA in 2001)

2) Your 70 year old grandma bowling 5 straight perfect 300 games (she has a 90 pin average, about 1 strike per game)

3) All 16 games in an NFL week end in a tie. (about 1 in 256 are ties)

4) Finding a collision while generating 1 Trillion keys per second in the next 100 years.


Title: Re: Randomly Finding Private Keys in Use
Post by: PenAndPaper on November 27, 2013, 06:12:39 PM

Ranking game: Please rank from most likely to least likely.

1) Barry Bonds type player hitting 250 home-runs in 664 Plate Appearances (He hit 73 in 664 PA in 2001)

2) Your 70 year old grandma bowling 5 straight perfect 300 games (she has a 90 pin average, about 1 strike per game)

3) All 16 games in an NFL week end in a tie. (about 1 in 256 are ties)

4) Finding a collision while generating 1 Trillion keys per second in the next 100 years.

I 'm from europe i can't evaluate none of them but i 'll make a wild guess. 4 is the least to happen  :P :P :P


Title: Re: Randomly Finding Private Keys in Use
Post by: Lauda on November 27, 2013, 06:30:36 PM

Ranking game: Please rank from most likely to least likely.

1) Barry Bonds type player hitting 250 home-runs in 664 Plate Appearances (He hit 73 in 664 PA in 2001)

2) Your 70 year old grandma bowling 5 straight perfect 300 games (she has a 90 pin average, about 1 strike per game)

3) All 16 games in an NFL week end in a tie. (about 1 in 256 are ties)

4) Finding a collision while generating 1 Trillion keys per second in the next 100 years.
Okay I've put all bets for NFL this week to result in a tie.
Wish me luck.


Title: Re: Randomly Finding Private Keys in Use
Post by: spacecaptain on November 27, 2013, 06:37:14 PM
good luck!!


Title: Re: Randomly Finding Private Keys in Use
Post by: Ricke on November 27, 2013, 06:49:50 PM

Ranking game: Please rank from most likely to least likely.

1) Barry Bonds type player hitting 250 home-runs in 664 Plate Appearances (He hit 73 in 664 PA in 2001)
Unsure

2) Your 70 year old grandma bowling 5 straight perfect 300 games (she has a 90 pin average, about 1 strike per game)
Unsure

3) All 16 games in an NFL week end in a tie. (about 1 in 256 are ties)
If 1 tie = 1:256, then 16 ties are 1:25616 = 1:2128

4) Finding a collision while generating 1 Trillion keys per second in the next 100 years.
1 trillionen (Americian English) = 1 000 000 000 000
100 Years = 100 x 365.25 x 86 400 = 3 155 760 000 seconds
1 000 000 000 000 x 3 155 760 000 = 3 155 760 000 000 000 000 000 total combinations (≈ 271.42)
Possible Bitcoin addresses: 2160
Probability = 1 : (2160 / 271.42) ≈ 1 : 288.58 of finding the private key of an arbitrary address (finding the collision of any used address raises the chances).


Summary:
3) 1:2128
4) 1:288.58

4 is more probable than 3!



Title: Re: Randomly Finding Private Keys in Use
Post by: PenAndPaper on November 29, 2013, 12:07:02 PM
(finding the collision of any used address raises the chances).

That's what a collision is. Having any 2 identical addresses so your math are wrong. Finding a collision raises the chances by alot.
Still it's not going to happen.


Title: Re: Randomly Finding Private Keys in Use
Post by: Ricke on November 29, 2013, 01:20:14 PM
(finding the collision of any used address raises the chances).
That's what a collision is. Having any 2 identical addresses so your math are wrong.
Sorry, I calculated with the implicit understanding that the attacker's giant address repository has to collide against the victim's tiny address pool.


Title: Re: Randomly Finding Private Keys in Use
Post by: PenAndPaper on November 29, 2013, 01:36:03 PM
(finding the collision of any used address raises the chances).
That's what a collision is. Having any 2 identical addresses so your math are wrong.
Sorry, I calculated with the implicit understanding that the attacker's giant address repository has to collide against the victim's tiny address pool.

Indeed. Btw if you want still to do the maths for collision you should use the birthday paradox as a reference


Title: Re: Randomly Finding Private Keys in Use
Post by: ajax3592 on November 29, 2013, 02:01:20 PM
Well if someone had a server farm they might try brute-forcing to shift the probability decimals a few places right here -  

0.00000000000000000000000000000000615%


Title: Re: Randomly Finding Private Keys in Use
Post by: theecoinomist on November 30, 2013, 10:03:29 PM
https://i.imgur.com/ruckRJ9.png