edwards.txt

Edwards curves are now supported for ECC.

There are some limitations. In particular the pairings programs will NOT
work with Edwards curves. However for ECC programs they will be faster 
than using the standard Jacobian/Weierstrass method.

To enable Edwards curves (and disable standard curves), simply insert

#define MR_EDWARDS

into mirdef.h

and recompile the MIRACL library

Note that the SCHOOF and SEA applications have now been modified to 
accept a flag -E which now looks for curves in Edwards form. Note that
these programs must be compiled *without" setting MR_EDWARDS. (They accept
the curve in twisted inverted Edwards form, convert to Weierstrass form, 
and count the points on that, before converting back to Edwards). 

An example parameter file describing an edwards curve is in the file 
edwards.ecs

If MR_EDWARDS is defined, alternative code to support edwards curves is
used in modules mrcurve.c and mrecn2.c. Note that curves over 2^m are not
affected.

To test, proceed as above to build the MIRACL library, compile and run 
the ECDSA (Elliptic Curve Digital Signature) test programs ecsgen.c, 
ecsign.c and ecsver.c, and also the ebrick.c program

Note that some programs like pk-demo.c are "hard-wired" to a non-edwards
curve, and will not work in this way. The CM program will not work with 
Edwards curves.