Not if he is able to export the private keys of his web wallet.
Got hacked yesterday. Sr. member account
Email was changed and password also.
I locked my account by clicking email that is sent when email address is changed.
My question is how I generate message to get verifyed message? Never done that
I don't have bitcoin wallet on PC. I use onlinewallets.
Be a bit more specific, please.
What webwallet where you using, i assume blockchain.info? You will need to export your private keys from there in order to sign a message from your account.
Exporting from blockchain.info is rather difficult, but possible, since everything is generated locally in a .json file.
I've used the following guide in the past, you should try it,
https://docs.google.com/document/d/1-2l6xOqcbjs9QWEqSh72RD1d8EEdvG_hQuEXw_f_o6w/editIf you were using a webwallet like coinbase, then yes, you're doomed and there is no way of signing a message with an adress from them.