Randomly Finding Private Keys in Use

[spacecaptain]

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/

[anti-scam]

Even better, you can keep your money in multiple addresses to make the already astronomically low probability even lower.

[PenAndPaper]

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.

[spacecaptain]

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.

[TomHirsch]

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.

[TTBit]

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.

[PenAndPaper]

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 

[Lauda]

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.

[spacecaptain]

good luck!!

[Ricke]

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 (≈ 2^71.42)
Possible Bitcoin addresses: 2¹⁶⁰
Probability = 1 : (2¹⁶⁰ / 2^71.42) ≈ 1 : 2^88.58 of finding the private key of an arbitrary address (finding the collision of any used address raises the chances).


Summary:
3) 1:2¹²⁸
4) 1:2^88.58

4 is more probable than 3!

[PenAndPaper]

(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.

[Ricke]

(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.

[PenAndPaper]

(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

[ajax3592]

Well if someone had a server farm they might try brute-forcing to shift the probability decimals a few places right here -  

0.00000000000000000000000000000000615%

[theecoinomist]