"Owning" a public key makes no sense.  You can say you posses the private key that maps to that public key.  You can say by possessing the private key you "own" any BTC that have been sent to the public key.  You are correct, bitcoins themselves cannot be stolen, Bitcoin addresses and public keys cannot be stolen.  The only thing that matters, the only thing that can be stolen, is the private key.

The public key is just a point on a curve with no usefullness or value without the private key.  Who owns the number 1234567?  Or better yet who owns the point on the unit circle at x=1, y=0?

Generally someone can prove "ownership" of Bitcoins by signing a short message with the private key used to control them.  If two people have the same private key then, as stated above, it would be a race to see who transfers them first to an address that they control by themselves.

I think there are more interesting cases:

Now an address can be set up to require M of N signatures to move the coins.  For example an address can be set up to require two out of three signatures in order to move the Bitcoins.  If three different people have the three different private keys and it takes two of them to move the coins, who "owns" the coins?

14 inputs to be exact.

Thanks.  You made my day with that one.

THANKS!!!  Based on your post I just sold all my BTC.  I sure hope you are right.  If not, I am sure going to be pissed at you.

You already do this every time you use SSL at some silly web site, like this one for example.

Is it possible that not all Bitcoin addresses are equally difficult to reverse engineer?

   No.

Are "even" numbers less secure than "odd"?

   No.

Does a higher percentage of alpha characters (rather than numeric) represent higher security?

   No.

Are there portions of an elliptical curve that are computationally more difficult?

   No.

I know one use that would be totally "end of Bitcoin" horrible:

Take the Bitcoin address, reverse all three hashes and wala you have one of the (on average) 2⁹⁶ possible public keys for that Bitcoin address!!!

OMG, end of the world, etc., etc.

Oh, wait, turns out that is really not all that much of a problem.

Still thinking...

So you are boycotting stuff made in China?

I don't think that is a word or phrase.  Not English anyway.  What were you searching for?

Sounds like a great idea for another alt coin:  "MoralCoin" or something like that...

Crap, not another 51% stupididy thread - when 1,000 threads on the same damn subject is not enough.

J P Morgan =/= Morgan Stanely

Did you try localbitcoins.com?

Hmmm.  The method I described would require you to use the mod 2^32 thirty-two times and it does not simplify as you suggested (the mod cannot be pulled out of the formula).  It also requires you to use integer math, not floating point, or figure out a way to throw away the fractional part of all the divides.

If you add mod 2^32 and use integer math (or throw away the fractional parts of the divides) then you have a solution, otherwise no.

Thanks.

Were you logged into your blockchain.info account already today (already entered the 2FA for today)?

[Hmmm.  Maybe I will change my 2FA to "every time" instead of "once per day" - now that I think about this]

Coins are now here:

https://blockchain.info/address/1ASzhmigL24UtZXPuoDMPwXdAxqygsg4WQ

Have not moved yet.

I guess you should forward the email to someone here who is brave enough to look into it (not me - not my area of expertise).

Would anyone care to see if they can find out anyting about the email?

I love puzzles and work is slow right now.  Speaking of work, got a meeting, be back later.