pub/ed{25519,448}.c: Double by adding self, rather than multiplying by two.

[catacomb] / pub / ed25519.c

diff --git a/pub/ed25519.c b/pub/ed25519.c
index 7fddf98..676fe8c 100644 (file)
--- a/pub/ed25519.c
+++ b/pub/ed25519.c
@@ -232,7 +232,7 @@ static void ptdbl(f25519 *X, f25519 *Y, f25519 *Z,
                                        /* (E = a C = -C) */
   f25519_sub(&t0, &t2, &t1);           /* t0 = F = D - C = E + D */
   f25519_sqr(&t1, Z0);                 /* t1 = H = Z0^2 */
-  f25519_mulconst(&t1, &t1, 2);                /* t1 = 2 H */
+  f25519_add(&t1, &t1, &t1);           /* t1 = 2 H */
   f25519_sub(&t1, &t0, &t1);           /* t1 = J = F - 2 H */
   f25519_mul(X, X, &t1);               /* X = (B - C - D) J */
   f25519_mul(Y, Y, &t0);               /* Y = -F (E - D) */