Quote from: aws on June 16, 2016, 08:25:52 PM

Question:
Since I am not a cryptographer and my cryptography classes gave me killer headaches, this question may have an obvious answer that i am not aware of.
I would like a way to change the private key of a public address, for this you'd of course require the current private key. Is this at all possible?

Why is this useful you ask?
Untraceable transfer of bitcoins.
Why would we want that you ask?
Financial privacy.

Would love to hear from those who have something meaningful to contribute

Addresses don't actually exist at the protocol level. Addresses are just an easy way for us humans to exchange a standard set of output script requirements.

The typical single key (pay-to-pubkey-hash) addresses that start with a 1 have exactly 1 private key associated with them. The public key is calculated from the private key using elliptic curve point multiplication, so asking if you could have a different private key is a bit like asking if you could raise 7 to some power other than 3 and still get an answer of 343. It simply isn't mathematically possible.

On the other hand, there are also pay-to-script-hash addresses that start with a 3. These addresses can set up requirements of one (or more) signatures from a set of many different private keys. In that case, you would have a list of several private keys that would all be able to spend an output that was sent to the address.