What about BTC I hold at an exchange? Would I need to move all my BTC to a personal BTC wallet before nucleus?
Yes. The correct way to implement this kind of distribution model is to pick a block number (eg. 290000), and say that bitcoins at that specific block are what gives you aethereum. Otherwise, you can claim some AETH with your BTC, deposit and withdraw from an exchange, claim more AETH, and repeat ad infinitum. For the system to be trust-free and secure, it would have to be based on private key signing, which means that you would have to have them in a personal wallet.
If you don't want to set up a new wallet and deal with different addresses another somewhat technical alternative is to use my pybtctool toolkit to generate a brainwallet and put your money all in the one address just before the nucleus happens. Pybitcointools/pybtctool includes Electrum message signing functionality with the "ecdsa_sign" command; here's an example session:
Code:
vub@shadowcow-200 00:29:41: pybtctool ecdsa_sign hullo `pybtctool sha256 cow`
GykcIAXZ3VxuSUfLBi+FCWnvKlEOmo13ysGfVWVfo2cobJhbWhFqMxrxgVB5cnPax+YUJqB1fk9Hkm8bYjoUuBE=
vub@shadowcow-200 00:29:48: pybtctool ecdsa_recover hullo GykcIAXZ3VxuSUfLBi+FCWnvKlEOmo13ysGfVWVfo2cobJhbWhFqMxrxgVB5cnPax+YUJqB1fk9Hkm8bYjoUuBE=
04334ec322ef674d8a91a5467b78cb12fab3de961aa3d6c2d6afd844526e18c8dd12e9b21d5f9411dfa37689c551d2572465f633df73b0d12015aeb72d423e0d30
Vitalik, I just noticed nobody responded to your post earlier and want to acknowledge you for contributing your thoughts on this idea despite its potential to undermine your Ethereum project as it stands.
As for asking people who would like to claim their 'spin-off' alt coins (æther or whichever) to actually move their bitcoins I would prefer an option that doesn't require that if it can be done reliably (such as the block-specifying method you propose). For those with cold storage wallets the private keys of which have never seen the light of day it is (from my limited understanding) less cumbersome to set up a means of temporarily importing a private key to a wipable off-line pc for signing a message to claim the spin-off coins than to require sweeping a wallet then having to generate and create new ones.
