hacking bitcoin transactions

[maokoto]

Do not understand it much, I am not hi-tech into bitcoin... but it is likely that your hacked transaction would not be the one accepted because other nodes will get the transaction and confirm it before you?

[shorena]

Do not understand it much, I am not hi-tech into bitcoin... but it is likely that your hacked transaction would not be the one accepted because other nodes will get the transaction and confirm it before you?

No, the reason is:

You're missing signatures.

And to make one of them you need private keys.

You can "hack" (as in change) the transaction all you want. If you want the coins to go elsewhere you either need the private key (so the coins are yours anyway) or the signature will be invalid and the transaction not accepted.

[avw1982]

All transactions, as previously mentioned, are encrypted with digital keys. You would have to be an excellent programmer to break the encryption.

Yeah they can try to break, But Bitcoin protocol uses combination of 2 of the strongest non-classified algorithms used by the NSA for encrypting Secret level documents and Breaking the signing algorithm requires a selective forgery attack or stronger and means that arbitrary transactions may be forged and entered into the system.

[helloeverybody]

I'm sure it's not possible and its best for everyone that it never is.  Bitcoin hack would be catastrophic.

[DuddlyDoRight]

If I'm an attacker with the intention of cheating for coins I'm going to look in to forking and mining delayed blocks..

If you have enough money for this kind of attack you maybe can rollback/invalidate transactions but you are not able grab the coins from these transactions.

I've read somewhere it might be possible to hide blocks that you can mine before they are broadcasted too. I forget the specs to the theory but it probably required controlling a peer or something to do with forks or fee-delays.

[jaydipmodhwadia]

Would controlling a mass node (by that I mean like all the nodes on blockchain) mean that you could perchance have the ability to control the whole blockchain?

[Decoded]

They aren't encrypted, but you can't broadcast them as your own. You're missing the tx signature. You also need all the other miners to confirm you transaction. You know how hard it is to change a transaction with even one transaction?