diff options
Diffstat (limited to 'crypto/ec/ecp_nistz256.c')
-rw-r--r-- | crypto/ec/ecp_nistz256.c | 57 |
1 files changed, 40 insertions, 17 deletions
diff --git a/crypto/ec/ecp_nistz256.c b/crypto/ec/ecp_nistz256.c index 564a8894b9..dca3a2dde5 100644 --- a/crypto/ec/ecp_nistz256.c +++ b/crypto/ec/ecp_nistz256.c @@ -335,19 +335,16 @@ static void ecp_nistz256_point_add(P256_POINT *r, const BN_ULONG *in2_y = b->Y; const BN_ULONG *in2_z = b->Z; - /* We encode infinity as (0,0), which is not on the curve, - * so it is OK. */ - in1infty = (in1_x[0] | in1_x[1] | in1_x[2] | in1_x[3] | - in1_y[0] | in1_y[1] | in1_y[2] | in1_y[3]); + /* + * Infinity in encoded as (,,0) + */ + in1infty = (in1_z[0] | in1_z[1] | in1_z[2] | in1_z[3]); if (P256_LIMBS == 8) - in1infty |= (in1_x[4] | in1_x[5] | in1_x[6] | in1_x[7] | - in1_y[4] | in1_y[5] | in1_y[6] | in1_y[7]); + in1infty |= (in1_z[4] | in1_z[5] | in1_z[6] | in1_z[7]); - in2infty = (in2_x[0] | in2_x[1] | in2_x[2] | in2_x[3] | - in2_y[0] | in2_y[1] | in2_y[2] | in2_y[3]); + in2infty = (in2_z[0] | in2_z[1] | in2_z[2] | in2_z[3]); if (P256_LIMBS == 8) - in2infty |= (in2_x[4] | in2_x[5] | in2_x[6] | in2_x[7] | - in2_y[4] | in2_y[5] | in2_y[6] | in2_y[7]); + in2infty |= (in2_z[4] | in2_z[5] | in2_z[6] | in2_z[7]); in1infty = is_zero(in1infty); in2infty = is_zero(in2infty); @@ -436,15 +433,16 @@ static void ecp_nistz256_point_add_affine(P256_POINT *r, const BN_ULONG *in2_y = b->Y; /* - * In affine representation we encode infty as (0,0), which is not on the - * curve, so it is OK + * Infinity in encoded as (,,0) */ - in1infty = (in1_x[0] | in1_x[1] | in1_x[2] | in1_x[3] | - in1_y[0] | in1_y[1] | in1_y[2] | in1_y[3]); + in1infty = (in1_z[0] | in1_z[1] | in1_z[2] | in1_z[3]); if (P256_LIMBS == 8) - in1infty |= (in1_x[4] | in1_x[5] | in1_x[6] | in1_x[7] | - in1_y[4] | in1_y[5] | in1_y[6] | in1_y[7]); + in1infty |= (in1_z[4] | in1_z[5] | in1_z[6] | in1_z[7]); + /* + * In affine representation we encode infinity as (0,0), which is + * not on the curve, so it is OK + */ in2infty = (in2_x[0] | in2_x[1] | in2_x[2] | in2_x[3] | in2_y[0] | in2_y[1] | in2_y[2] | in2_y[3]); if (P256_LIMBS == 8) @@ -1273,6 +1271,8 @@ __owur static int ecp_nistz256_points_mul(const EC_GROUP *group, } else #endif { + BN_ULONG infty; + /* First window */ wvalue = (p_str[0] << 1) & mask; idx += window_size; @@ -1285,7 +1285,30 @@ __owur static int ecp_nistz256_points_mul(const EC_GROUP *group, ecp_nistz256_neg(p.p.Z, p.p.Y); copy_conditional(p.p.Y, p.p.Z, wvalue & 1); - memcpy(p.p.Z, ONE, sizeof(ONE)); + /* + * Since affine infinity is encoded as (0,0) and + * Jacobian ias (,,0), we need to harmonize them + * by assigning "one" or zero to Z. + */ + infty = (p.p.X[0] | p.p.X[1] | p.p.X[2] | p.p.X[3] | + p.p.Y[0] | p.p.Y[1] | p.p.Y[2] | p.p.Y[3]); + if (P256_LIMBS == 8) + infty |= (p.p.X[4] | p.p.X[5] | p.p.X[6] | p.p.X[7] | + p.p.Y[4] | p.p.Y[5] | p.p.Y[6] | p.p.Y[7]); + + infty = 0 - is_zero(infty); + infty = ~infty; + + p.p.Z[0] = ONE[0] & infty; + p.p.Z[1] = ONE[1] & infty; + p.p.Z[2] = ONE[2] & infty; + p.p.Z[3] = ONE[3] & infty; + if (P256_LIMBS == 8) { + p.p.Z[4] = ONE[4] & infty; + p.p.Z[5] = ONE[5] & infty; + p.p.Z[6] = ONE[6] & infty; + p.p.Z[7] = ONE[7] & infty; + } for (i = 1; i < 37; i++) { unsigned int off = (idx - 1) / 8; |