In the forth and final post in this series on passwords, I’ll talk to you about rainbow tables. I think the best way to get people to create and use good passwords is to teach them how passwords are cracked.
Long ago, when UNIX-like systems were used as shared servers and most people logged into them with “dumb terminals”, users could see who else had accounts on the system. This was convenient, especially in work or academic environments and acted as a directory of sorts. So if Alice wanted to send an email message to Bob, she would just log on to the system and look at a file called /etc/passwd. This file showed each person’s username, name, and other information. This file also contained each users password in the form of something called a hash. Trend Micro explains that, “Hash values can be thought of as fingerprints for files”. The hash is a mathematical representation of the password that cannot be reversed or