Question

a precomputed table of hash values that can be used to reverse hash functions. For example, if a plaintext password has been protected by hashing it, you may be able to use a _______ to reverse the hashing function and expose the original plaintext password.

Answer 1

A precomputed table used to reverse hash functions and decrypt hashed passwords is called a rainbow table. It enables password cracking by matching hash values against the table. The effectiveness of rainbow tables can be mitigated with the use of salts in hash functions.

Step-by-step explanation:

A precomputed table of hash values that can be used to reverse hash functions is known as a rainbow table. Rainbow tables are used to perform a time-memory trade-off attack to decrypt hashed values, often used in password cracking. The way it works is by comparing the hashed password against a table of precomputed hash values until a match is found, revealing the original plaintext password. These tables take advantage of the fact that many hash functions can potentially hash multiple inputs to the same output, a circumstance known as a collision.

However, it is crucial to note that the use of salt in hashing passwords can greatly reduce the effectiveness of rainbow tables. By adding a unique value to each password before it is hashed, the resulting hash will be unique even if the underlying password is not, thereby necessitating unique rainbow tables for each salt value, which makes the process impractical due to the immense size of the tables required.