Precomputed Hashes

C.

The answer is C. Rainbow tables.

Rainbow tables are a type of password cracking technique that uses precomputed hashes to guess passwords. A hash is a one-way encryption function that transforms a password or other data into a fixed-length string of characters. In order to verify a password, the hash of the entered password is compared to the hash of the correct password. If the two hashes match, the password is considered correct.

Rainbow tables work by precomputing the hashes of a large number of possible passwords and storing them in a table. When a password hash needs to be cracked, the rainbow table is searched for a matching hash. If a matching hash is found, the corresponding password is considered to be the correct password.

Rainbow tables can be very effective at cracking passwords because they can quickly search through a large number of possible passwords. However, rainbow tables are limited by the size of the table and the amount of time it takes to generate the table. Additionally, if the passwords are salted (a technique that adds a random string to the password before hashing it), then rainbow tables become less effective.

Iptables and NAT tables are both network security technologies that are used to control access to a network. They are not related to password cracking.

ARP tables are used in networking to map IP addresses to MAC addresses. They are not related to password cracking either.