patents
Does publication remove patent protection?
<p>I found the following publication: <em><a href="http://link.springer.com/chapter/10.1007%2F3-540-48059-5_27" rel="nofollow noreferrer">Fast Multiplication on Elliptic Curves over GF(2^m) without Precomputation</a></em> which </p>

<blockquote>
  <p>describes an algorithm for computing elliptic scalar multiplications
  on non-supersingular elliptic curves defined over GF(2^m).</p>
</blockquote>

<p>In the paragraph 4.2 a version using projective coordinates is described to avoid field inversions in GF(2^m) (please refer to the publication for unknown variables).</p>

<p><a href="https://i.stack.imgur.com/Uq9e3.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Uq9e3.png" alt="enter image description here"></a></p>

<p>On the other hand, I found the following patent: <em><a href="http://www.google.com/patents/EP0874307A1?cl=zh" rel="nofollow noreferrer">Accelerated finite field operations on an elliptic curve</a></em> which presents </p>

<blockquote>
  <p>A method for multiplication of a point P on elliptic curve E by a
  value k in order to derive a point kP comprises the steps of
  representing the number k as vector of binary digits stored in a
  register and forming a sequence of point pairs (P1, P2) wherein the
  point pairs differed most by P and wherein the successive series of
  point pairs are selected either by computing $(2mP,(2m+1)P)$ from
  (mP,(m+1)P) or ((2m+1)P,(2m+2)P) from (mP,(m+1)P). The computations
  may be performed without using the y-coordinate of the points during
  the computation while allowing the y-coordinate to be extracted at the
  end of the computations, thus, avoiding the use of inversion
  operations during the computation and therefore, speeding up the
  cryptographic processor functions.</p>
</blockquote>

<p>From my point of view, the algorithm presented in the publication is a particular case of the invention described in the patent. Plus it is well known that there are a lot of patents about ECC over binary fields. But I have a little doubt because one of the author of the publication (Julio Lopez) is from the same university of the patent authors (university of Waterloo).</p>

<p>So my question is the following: <strong>Can I use the publication to perform ECC without being under patent protection? More generally, can an academic publication be under patent protection?</strong></p>

<p>To answer the specific questions you asked:</p>

<blockquote>
  <p>Can I use the publication to perform ECC without being under patent protection?
  Can an academic publication be under patent protection?</p>
</blockquote>

<p>The answers are:</p>

<ul>
<li><p>No, that academic paper does not provide any protection from patent litigation.</p></li>
<li><p>Yes, an academic paper can publish the details of an invention, and that in no way voids the patent.</p></li>
</ul>

<p>The issue is the timing of the publication; the patent was filed in 1998; the academic paper was published in 2002.  Once a patent is filed, the inventors (or anyone else, for that matter) can publish the patent, and that in no way invalidates the patent.  To provide any protection against a patent, the prior art needs to be "prior", that is, earlier than the filing date of the patent.</p>

<p>Now, this particular issue is made a bit tricky because there does appear to be prior citations of this invention.  The whole reason this invention is called the "Montgomery ladder" (not Montgomery multiplication - that's something else) was because it was first published by Peter Montgomery in 1987.  One would think that would invalidate the patent.  However, I'm not an attorney; I cannot advise you to proceed under that assumption.</p>

<p>Instead, I would suggest you follow the advice of Joao; there are plenty of elliptic curve routines out there; use one of them.</p>
