Imagine two PBKDF2-SHA-512 hashes of the same password are generated. Each has individual salt. If an attacker had one hash and the salt of both hashes, would he be able to compute the missing hash or would he gain a significant advantage guessing it?
My situation: A user inputs a password that should be used for AES encryption. The password is hashed once to get a AES Key. Then a second hash of the password the user entered is generated with a different salt than the first one and is sent to the server together with the salts of both hashes. Can a attacker who hijacked the server, calculate the hash that is used as AES key?