A two-factor authentication system is quite common; despite its pompous name, it’s fairly easy to use and understand – we shall call it a double safety net for your online accounts. Banks, Facebook, Google and now Twitter, are all using such a system, but there’s a problem: Kim Dotcom claims patent over it.

Not long after Twitter announced that their service is introducing the two-factor system, a tweet from Kim Dotcom read that Google, Facebook, Twitter, Citibank, and other services (that use the same system) are using his invention without permission.

Dotcom’s claim is somewhat true – the two-factor authentication technology is indeed patented under his name (Kim Schmitz) on US territory (he filed for it in 1998 and was granted the patent two years later). Furthermore, according to a blog post by Emily Weal, Kim had rights over the technology in Europe as well, but lost them in 2011 when AT&T proved to have the patent granted earlier than Kim’s – in 1995.

To make things even more complicated, AT&T, Ericsson and Nokia all have patents over TFA on US territory, also before Kim did.

While the German entrepreneur accused the aforementioned American corporations of stealing his invention, he added that:

“I never sued them. I believe in sharing knowledge & ideas for the good of society. But I might sue them now cause of what the U.S. did to me.”

Then, after some deep thinking, he wrote:

“We are all in the same DMCA boat. Use my patent for free. But please help funding my defense.”

“My U.S. 2FA patent has no prior art because it specifies the use of a mobile phone & SMS. Unfortunately my EU patent wasn’t specific enough. The prior art that killed my EU patent was an old school pager,” Kim said.

While it’s true that AT&T’s patent (in the US) focuses on pagers, it continues to underline that “it will be obvious to those skilled in the art that many other communications mechanisms may be used instead of, or in addition to, wireless paging devices. These mechanisms include, for example, cellular telephones, conventional wired telephones, personal computers, etc.”