The United States Patent and Trademark Office is reexamining one of the key patents in the battle between Apple and Samsung. Specifically, it is claiming that design patent D618677 — essentially the front of the iPhone 3G — was not sufficiently described by Apple. The decision could affect the size of the damages that Samsung is supposed to pay Apple, but a final number won't be determined for a while as the case is still with the courts awaiting a third trial.

Apple originally submitted this patent in November of 2008, but in the filing the company leaned heavily on two of its previous patents in order to give D618677 a "priority" protection date of January 5th, 2007. By doing this, the company essentially gave the patent two extra years of life that it could use to challenge competitors with similar designs. The new decision from the USPTO is that Apple did not sufficiently describe the D618677 patent enough to enjoy that protection, and so now the protection only extends back to the filing date of November 2008.

That's a big problem for Apple because, in that almost two-year gap, a number of competitors' phone designs ("prior art" in patent parlance) are so obviously similar to the design spelled out in D618677. In a legal sense, it's now as if Apple tried to file a patent in 2008 on a design that — by that time — was so common that the patent would never have been awarded in the first place.

By losing that protection date of January 5th, 2007, the company could also lose a major part of its foundation for the massive $1 billion in monetary damages it was originally awarded in 2012. That $1 billion has already been challenged, too — just a few months ago, the United States Court of Appeals for the Federal Circuit cut into it by a few hundred million, and a third trial is now necessary to determine the final amount.

Correction: This article originally stated that the USPTO had invalidated patent D618677. The patent is only being reexamined and has not been completely invalidated. The article has been updated to reflect this.