Let's say your scheme consists of the following: your name, the year you were born, your favorite number, and the website that you're making a password for. The hash length is set to 6 and the setting for truncating style which decides what part of the hash to remove to trim it down is set to trim the ends. Additionally, you made a prefix to add to the hash to ensure there is a capital and lowercase letter along with a number and symbol which you make: Aa1!
Then the scheme for Google might be:
- Your name: John Smith
- The year your were born: 80
- Your favorite number: 12
- The website: google.com
The MD5 hash generated would be: i/mXS/hpizJk+cglvUDVUQ==
Removing the ends so that there are only 6 characters would leave: zJk+cg
Adding the prefix makes the end result: Aa1!zJk+cg
And the scheme for Apple would then be the same except for #4 (the website):
- Your name: John Smith
- The year your were born: 80
- Your favorite number: 12
- The website: apple.com
The MD5 hash generated would be: Z0hBNYuAPgTOCGGC2uswEQ==
Removing the ends so that there are only 6 characters would leave: gTOCGG
Adding the prefix makes the end result: Aa1!gTOCGG
So just by changing the website of the service your password changes from Aa1!zJk+cg for Google and Aa1!gTOCGG for Apple.
Hackers would have no idea how it is you come up with your passwords and your passwords would now be different for every service yet making them is far more familiar to you than a randomly generated key.