Newbie question about private and public keys

[iraszl]

I know this is elementary and can't be done but I couldn't find a satisfactory answer in google, so here it goes:

What prevents somebody from 'guessing' the private key that matches a public key?

Theoretically if someone managed to try and match all combinations of the 256-bit private key between 0x1 and 0xFFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFE BAAE DCE6 AF48 A03B BFD2 5E8C D036 4141 to a public key he would eventually be able spend the bitcoins stored on this account right?

What does it take to see if a private/public key combination is correct? Is this something you check against the bitcoin network or is it a local algorithm?

Thanks!

[Foxpup]

I don't think you realise just how big the numbers involved really are. Theoretically, if someone managed to try and match all combinations of 256-bit keys, he would need to consume billions of times more energy than an exploding supernova, in which case you've got bigger problems than your bitcoins.

[yogi]

[iraszl]

Thank you!

[Sonny]

This is a good illustration on the problem.
Where is it originally from?

[cz_miner]

Excellent pic! Will print it out and put in my office.

http://miguelmoreno.net/wp-content/uploads/2013/05/fYFBsqp.jpg

[Cryptopher]

I know this is elementary and can't be done but I couldn't find a satisfactory answer in google, so here it goes:

What prevents somebody from 'guessing' the private key that matches a public key?

Theoretically if someone managed to try and match all combinations of the 256-bit private key between 0x1 and 0xFFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFE BAAE DCE6 AF48 A03B BFD2 5E8C D036 4141 to a public key he would eventually be able spend the bitcoins stored on this account right?

What does it take to see if a private/public key combination is correct? Is this something you check against the bitcoin network or is it a local algorithm?

Thanks!

I understand your concern, but it isn't something that you need to worry about. Yes there is a private/public key pair according to some cipher, but nobody is going to figure out your private key from your public key.

The biggest threat is people gaining access to your machine/private information through poor security practice (human's are usually the weak link in security). If somebody gets these details through poor security then all they need to do is walk straight through the door to your precious coins.

Stay safe

[Cryptopher]

That's amazing haha. Of course there is always universally BAD luck But more than likely there is bad security practice, allowing the bad guy to walk straight in lol.

[yogi]

This is a good illustration on the problem.
Where is it originally from?

I'm not sure who originally created the image, hopefully someone will enlightens us.

[iraszl]

I understand your concern, but it isn't something that you need to worry about. Yes there is a private/public key pair according to some cipher, but nobody is going to figure out your private key from your public key.

The biggest threat is people gaining access to your machine/private information through poor security practice (human's are usually the weak link in security). If somebody gets these details through poor security then all they need to do is walk straight through the door to your precious coins.

Stay safe

Yes, if you have an unencrypted wallet and somebody steals it that's a bummer. Even if encrypted and you use '12345' as a password still not good. I guess you're only as safe as your password is, right?

Cold storage is the solution.