006 Encryption, Hashing & Salting Explained: How Linux Safely Stores Passwords 🔐

00:14 Theory About Encryption
06:08 Theory About Hashing
10:25 Theory About Salting
17:36 How Linux uses Salting to store password information.

In this video, we are going to talk about #Encryption, Encryption types, #Hashing and #Salting very briefly. And we will look into how does Unix/Linux store users' password information in the form of salted hash inside "/etc/shadow" file. In early days of Unix, password used to be stored in "/etc/passwd" file but since other users and application processes need to access passwd file to read user related information, they started storing password information in a separate shadow file inside /etc directory, which has a restricted access to root user only.

Other users who run "passwd" command to change their password executes the "passwd" command with the special (setuid/setguid) permission of the root user. So when they run the "passwd" command, they would be running it as a root just to update the shadow file. We will then look into "openssl" and "mkpasswd" commands to re-generate the salted hash password using different hashing algorithm.