Which of the following describes true statements regarding the process of uncovering passwords using a high$-$outcome password cracker?

a$.$ The notion of high outcome is only possible when passwords are stored in plaintext.

b$.$ It applies reverse$-$engineering techniques to uncover passwords based on entries in digest files.

c$.$ It uses an online brute$-$force approach to cycle through combinations of characters to find a match.

d$.$ It compares an existing database of hashes with hashes in the stolen password file.