On Aug 20, 2013, at 1:38 PM, Perry E. Metzger wrote:

> What is the current state of patents on elliptic curve cryptosystems?
> (It would also be useful to know when the patents on such patents as
> exist end.)
As the Wikipedia article http://en.wikipedia.org/wiki/ECC_patents makes clear, 
the situation is ... unclear.  Certicom has a large number of patents, the most 
general of which seems to be http://www.google.com/patents/US6141420, which has 
a priority date of July 29, 1994 and a filing date of Jan 29, 1997 - so has 
another 3.5 years to go.  It also holds many other patents - the NSA says more 
than 130 related patents.  But their validity is unclear:  The only lawsuit 
mentioned (Certicom went after Sony) was settled, but Sony at the time was 
claiming prior art.  RSA asserts (but says this isn't a legal opinion) that all 
of Certicom's patents are on particular implementation techniques, and that 
other techniques can be used to avoid the patents.  There are related patents 
held by everyone from Cylink to HP to Apple.

With no cases argued all the way through, it's impossible to evaluate the 
strength or actual breadth of the claims.  The situation is unsettled enough 
that commercial implementors will generally avoid treading in the area except 
for the particular curve that NSA licensed and allowed for general use.  RSA 
seems willing to challenge that position:  As part of its BSAFE library, it 
provides elliptic curve implementations over a variety of curves, not, it 
seems, just the one NSA licensed 

                                                        -- Jerry

> Perry
> -- 
> Perry E. Metzger              pe...@piermont.com
> _______________________________________________
> The cryptography mailing list
> cryptography@metzdowd.com
> http://www.metzdowd.com/mailman/listinfo/cryptography

The cryptography mailing list

Reply via email to