DD Blue Blocks Menu is a Scripts software developed by Dynamic Drive. After our trial and test, the software is proved to be official, secure and free. Here is the official description for DD Blue Blocks Menu:

This is our rendition of a block looking vertical menu, inspired by the original Blue Blocks menu and based on the CSS used by the vertical menu of our sister site CSS Drive. It supports the insertion of menu headers to act as dividers between groups of menu links.