He will guide you, he doesn't ask for your wallet.dat file usually, he will assist you to extract the little data portion of the encrypted encryption key needed to find the wallet's encryption secret (no private key is exposed or compromised by this little data).
That's exactly what people tell me
That's because that's the safest way to ask someone to bruteforce a wallet.dat's master key encryption passphrase. (
a.k.a the wallet's password)
You can research how the wallet is encrypted here:
https://en.bitcoin.it/wiki/Wallet_encryptionThen double-check what the article said in the code:
/src/wallet/crypter.cpp and
/src/wallet/crypter.h(
open-source is amazing isn't it?)
Basically, what you'll give is just an encrypted "
master key" (
"mkey", not a master private key) which is encrypted with your password.
The "
wallet recovery service" will be able to decrypt it once he stumbled upon the correct password
But since it's just a decrypted master key, it's useless without the actual wallet.dat file where the private keys that's encrypted with that mkey.