Essentially what you're saying is you found a private key collision on the Ethereum blockchain, and Ethereum would be broken as a result of it (since you are claiming you got access to someone else's ~$400k worth of ETH/ETC and could fuck them over if you are successful in liquidating it). If this was true, it would have a devastating effect on ETH and crypto as a whole. Pretty bold claim - would love to see the proof of it.
At last someone who understands my point. Yes I did! And not only a key collision, but I have an equal deterministic way of generating ethereum private keys deterministically from a bitcoin entropic constant and hit ETH keys with balances in them.
I can share proofs but posting people's addresses in public with bal in them most still in use is not a polite thing to do... but in private i def would! (screenshots, address, private keys) whichever requested. I don't know much about ETH like i stated before, but i know quite enough about bitcoin.
Something is not right here.
Maybe you are extremely luck and found a collision. Whatever software you build cannot find collisions (it would be more lucrative to mine).
However, if you really make a software that can do it..... ( I doubt it since you are here in this forum on the wrong session asking for help.)
But anyway, if you truly did, just sell these ethereum, get rich and then destroy cryptocurrencies forever. Just spread the word that you can break private keys and cryptocurriencies will be dead soon.
Go to bitcoin technical discussion board and try to explain what you did there.
Look at the bottom of this page MOVE TOPIC button. Just click it and move this topic there.
There are knowledge people there who will makes things clear for you. Something is not right, I think you do not really own the private key of that address you are talking about, or you were extremely luck.