Cracking passwords

Passwords
When you type in a password, the computer converts whatever you type into a hash. A hash is a unique algorithmic value that is then stored on your computer (or Web server). "Computers have been designed this way for the last 20 years," said Graham, "so that when hackers break into your computers they can not just easily steal your passwords. All they can steal is that cryptographic information." Typically, passwords are stored in MD4 hash, says Graham.

Security Watch: Cracking passwords - CNET reviews