"It goes by many names, The Star of Bast, The Hand of Ullr, The Star of the Red Hand, even the Mediallian of Technological Invisibility. But what is known about it is that it is an ancient symbol, its parts have meaning in dozens of desperate faiths, and it is agreed to be a symbol of protection."
That's the fiction at least, this symbol appears in a number of fictional works written by yours truly, most notebly in the story "The November Uprising" which you can find here: http://thepandorasociety.com/short-story-the-november-uprising/
At it's basis is three different symbols, the Pentangle, the Hand of Fatima, and the Eye of Horus (left or right depending on how you wear the pendant).
The Pentangle, contrary to belief is not necessarily an "evil" symbol. A Christian use of the pentangle occurs in the 14th-century English poem Sir Gawain and the Green Knight, in which the symbol decorates the shield of the hero, Gawain, a knight of the round table. The unnamed poet credits the symbol's origin to King Solomon, and says the symbol is key to understanding the work. The poet explains that each of the five interconnected points represents a virtue tied to a group of five. Gawain is keen in his five, dextrous in his five fingers, faithful to the salvation provided through the Five Wounds of Christ, takes courage from the five joys that Mary had of Jesus, and exemplifies the five virtues of knighthood. In occult mysticism, the points of the pentangle correspond to the classical five elements of earth, air, fire, water, and aether/spirit. The point representing spirit traditionally points upward, symbolizing the spirit or will of humanity overcoming nature. It is only when the spirit point is downward that the pentangle gains a negative conotation.
The Hand of Fatima, also known as the Hamsa, is a universal sign of protection from evil, the image of the open right hand is seen in Ancient Mesopotamian, Greek, Egyptian, Phoenician, Hebrew, and Indian artifacts. It's still a common symbol used throughout the middle east today. Additionally when depected with the color red the symbol is associated with the ancient gaelic hero Labraid Lamdhaerg, the son of the Gaelic Sun God, and with the House of Ulster of Northern Ireland.
Finally there is the Eyes of Horus, also known as the Eyes of Ra, are ancient egyption symbols of protection. The right eye symbolizes the sun and protection from evil durring the day, while the left symbolizes the moon and protection from evil at night. Additionally the eyes are connected to the goddesses Wadjet, Bast, Sekhmet, Mut, and Hathor.
Ultimately this symbol was designed to encorporate these symbols in a natural way, to pay respect and homage to the cultures of the past, and to provide as much protection as possible.