Bitcoin Forum

Just a simple question, if the answer is no please tell me the minimum number you'd feel safe at.

EDIT: If no also, would 1 in 2,176,782,336 be enough or still no?

Of course not, 60M possibility would be broken in seconds.  I feel safe with SHA256.

How about 1 in 1.0638735892371651e+56?

Yes

I ride in a car almost every day.

Your odds of dying in a car crash, over the span of your entire life, are somewhere in between 1 and 50 and 1 and 100. When broken down on a per year basis, your odds of dying in a vehicle crash would somewhere in between 1 and 4,000 and 1 and 8,000.

Thank you for saying yes, but it would be extremely vulnerable to brute-force attacks. So I guess it's out of the question.

But which address? Yours? Mine? Random?

The number of addresses increases the odds.

I think 1 in 1e+109 would be the minimum that I would feel safe with today.

It isn't clear what you mean by "collision attack". I'm going to assume that you mean the chance of randomly guessing a key would be 1 in 60 million.

You specified the risk, but what about the loss, and the cost of the attack? If the loss is 1 satoshi, then I wouldn't feel safe, but I also wouldn't care.

On the other hand, if the loss is 1 BTC, then no. My laptop can check 60 million addresses in just a few seconds.

To protect 1 BTC, I would feel safe with at least a 1 in 1.5 x 10²⁰ chance, because then it would be more profitable to mine 1 BTC than to steal mine.

I'm pretty sure that the worst iteration of Bitcoin is magnitudes better than the best protected bank account. The scammers running Bitcoin exchanges and businesses make Bitcoin unsafe, not the design.

First of all, if you mean a physical collision attack like a car crash, this thread should be in off-topic.

But to answer your question, In in 10 000 000 000 would work well.  ;)

I believe in reducing the risk, by spreading my coins over multiple addresses with much smaller amounts. It might increase the risk for having more addresses, but the loss will be significant lower, IF it did happen. Who will have lost more? A person with 1000 bitcoins in one address or a person with 10 bitcoins in 100 Bitcoin addresses? < I would much rather lose small amounts than losing everything in one collision >

But that is just my screwed up logic, and to others this might pose a higher risk. My strategy has worked for 5 years and I have not lost a single Satoshi due to collisions. ^smile^

1 in 10 000 000 000 would still be cracked insanely fast.. You need big numbers with more than a 100 zeros to get safety from collission.

Luckily, that's exactly what bitcoin provides. And even when you get a collision, the address most likely does not hold any coins.

I follow a similar procedure but its probably pointless to do since a collision is so unlikely . there certainly hasnt been any random collisions so far by just creating a new address and im more than confident that no one has been able to brutefore any up to this point either. 1 in 60000000 could obviously be bruteforced though.

Nope, even if we assume full 256 bit there are only 78 decimal digits. For an unused (for paying, not receiving) address we can assume 160 bit (due to RIPEMD160) and for a used address 128 bit (due to ECDSA), so 49 and 39 decimal digits respectivly. If you must have 100 decimal digits to feel secure, bitcoin is too weak for you.