Commit c87bd88c by Niels Möller

### Comment fixes for ecc_add_eh

parent b33eea3b
 ... ... @@ -55,20 +55,26 @@ ecc_add_eh (const struct ecc_curve *ecc, #define z3 (r + 2*ecc->p.size) /* Formulas (from djb, http://www.hyperelliptic.org/EFD/g1p/auto-edwards-projective.html#doubling-dbl-2007-bl): http://www.hyperelliptic.org/EFD/g1p/auto-twisted-projective.html#addition-madd-2008-bbjlp Computation Operation Live variables C = x1*x2 mul C D = y1*y2 mul C, D T = (x1+y1)(x2+y2) - C - D C, D, T E = b*C*D 2 mul C, E, T (Replace C <-- D - C) T = (x1+y1)*(x2+y2) mul C, D, T - C - D E = b*C*D 2 mul C, E, T (Replace C <-- D+C) B = z1^2 sqr B, C, E, T F = B - E B, C, E, F, T G = B + E C, F, G, T x3 = z1*F*T 3 mul C, F, G, T y3 = z1*G*(D-C) 2 mul F, G x3 = z1 * F * T 2 mul C, F, G, T y3 = z1*G*(D+C) 2 mul F, G z3 = F*G mul 10M + 1S We have different sign for E, hence swapping F and G, because our ecc->b corresponds to -b above. */ #define C (scratch) #define D (scratch + 1*ecc->p.size) ... ... @@ -88,17 +94,17 @@ ecc_add_eh (const struct ecc_curve *ecc, ecc_modp_mul (ecc, x3, C, D); ecc_modp_mul (ecc, E, x3, ecc->b); ecc_modp_add (ecc, C, D, C); /* ! */ ecc_modp_add (ecc, C, D, C); ecc_modp_sqr (ecc, B, z1); ecc_modp_sub (ecc, F, B, E); ecc_modp_add (ecc, G, B, E); /* x3 */ ecc_modp_mul (ecc, B, G, T); /* ! */ ecc_modp_mul (ecc, B, G, T); ecc_modp_mul (ecc, x3, B, z1); /* y3 */ ecc_modp_mul (ecc, B, F, z1); /* ! */ ecc_modp_mul (ecc, B, F, z1); ecc_modp_mul (ecc, y3, B, C); /* Clobbers z1 in case r == p. */ /* z3 */ ... ...
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment