Understanding the Linux Password Security System is essential information for knowing how to keep your system secure. With this knowledge you can understand how to better protect your computer as well as how you can recover forgotten passwords by manually editing the password or shadow files.
This video will explain how the password systems are implemented including the /etc/passwd file and the /etc/shadow file. It explains what password hashing is, the security vulnerabilities of the MD5 hash and the safer options including SHA-512 and YesCrypt hashing.
It explains why the hash is different from encryption and how even the most secure hash algorithms are susceptible to certain types of hacker / cracker attacks, including dictionary and brute force attacks.
It then uses that knowledge to show how to take a Raspberry Pi for which you have lost the password and remove the password completely. This allows you to login to the Raspberry Pi and then reset your password.