Bitcointalk account is locked. Must send valid proof that can be easily and publicly verified to unlock account.

Signed message from PGP key. Or signed messages from bitcoin addresses used in genesis block up to block 170.

It's possible Satoshi may have lost the private keys or wallets, but he'd never lose access to his PGP key. Satoshi did remind everyone, never to delete wallets. He would have kept a backup somewhere.