Can't brute or rainbow table a salted HMAC, even if the keyspace were 10^10-10^13 because 1. nonces and 2. sufficient number of iterations, mem/cpu/gpu/asic-har

Can't brute or rainbow table a salted HMAC, even if the keyspace were 10^10-10^13 because 1. nonces and 2. sufficient number of iterations, mem/cpu/gpu/asic-hard, scrypt-style.