Mention CocksPinch{6,8,_k} files

README.md

@@ -13,6 +13,8 @@ We provide code for the following tasks.
    "Formulas for final exponentiation" in this file.
  * Search for pairing-friendly curves with our Cocks-Pinch variant; see
    "Using the search program".
+ * Elliptic curve object inherited from the sage object EllipticCurve to handle
+   pairing-friendly curves
 
 Computing pairing costs
 =======================
@@ -624,4 +626,23 @@ respectively):
 Note that the former is naturally preferred because hy has 2-naf weight
 only 4.
 
-
+Pairing-friendly curve objects
+==============================
+
+The files [`BN.py`](BN.py), [`BLS12.py`](BLS12.py), [`MNT6.py`](MNT6.py),
+[`KSS16.py`](KSS16.py) provide a class inherited from the sage class
+`EllipticCurve_finite_field` so that the usual methods are available.
+Moreover, the methods `beta`, `lamb` return integers for the GLV method (used in
+RELIC library to speed-up scalar multiplication), and the field `polynomial_p`
+returns a list of coefficients corresponding to the polynomial used to obtain
+the special prime $p$ to define a finite field $\mathbf{F}_p = GF(p)$ and then an
+elliptic curve $E(\mathbf{F}_p)$.  
+
+The files [`CocksPinch6.py`](CocksPinch6.py), [`CocksPinch8.py`](CocksPinch8.py)
+correspond to Cocks-Pinch curves with embedding degree $k=6$ and $D=3$, resp.,
+$k=8$ and $D=4$.  
+
+The file [`CocksPinch_k.py`](CocksPinch_k.py) is used for
+Cocks-Pinch curves that don't have a particular structure.
+The input parameters are obtained with the functions described above
+(`CocksPinchVariant`, `CocksPinchVariantResult`).