Good password hashing functions will not be much impacted by password length. If you stores the password with 128 bit (salted and key-stretched) hash, there's n

Good password hashing functions will not be much impacted by password length. If you stores the password with 128 bit (salted and key-stretched) hash, there's no gain in allowing passwords longer than 64 characters. Basically, limit the size of input parameters helps preventing DOS and Buffer Overflows.