Key stretching

Key stretching is a way to make it harder for someone to guess a password. Key stretching adds extra steps to the process of checking a password that makes it take a long time. It's like stretching a rubber band - it takes a lot of effort to stretch it, and that makes it hard for someone else to stretch it too. Key stretching makes it much harder for someone to guess a password because even if they guess it, they need to do a lot of extra work to make sure it's the right one.