I am wondering how much hashing a password used as key for a symmetric key algorithm helps preventing brute force attack on crypted text.
Let's assume I want to crypt text A using key B using AES-256. I expect user to input not secure keys, such as:
['apple', '22march', 'newyork'].
So I hash these keys with PBKDF2 using many iterations, and I got the key B. That is long and fixed length key I will use for crypting the text with AES.
Would this help preventing brute force attacks?
The attackers should also hash each input (for example from a dictionary, where they'll match 'apple') to get the key B for trying decrypting the text A using AES? Or alternatively, they should trying brute forcing directly the AES crypted text, but the keys are always output from PBKDF2 and so they are really difficult to be cracked.