From ba84265c483a484e608063e95c587799c8eed11f Mon Sep 17 00:00:00 2001 From: Adam Langley Date: Wed, 14 Dec 2016 16:04:10 -0800 Subject: [PATCH] Include some C versions of the x86-64 P-256 code. This change includes C versions of some of the functions from the x86-64 P-256 code that are currently implemented in assembly. These functions were part of the original submission by Intel and are covered by the ISC license. No semantic change; code is commented out. Change-Id: Ifdd2fac6caeb73d375d6b125fac98f3945003b32 Reviewed-on: https://boringssl-review.googlesource.com/12861 Reviewed-by: Adam Langley --- crypto/ec/p256-x86_64.c | 238 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 238 insertions(+) diff --git a/crypto/ec/p256-x86_64.c b/crypto/ec/p256-x86_64.c index 0a3be92a..9dea4fbd 100644 --- a/crypto/ec/p256-x86_64.c +++ b/crypto/ec/p256-x86_64.c @@ -39,6 +39,244 @@ #if !defined(OPENSSL_NO_ASM) && defined(OPENSSL_X86_64) && \ !defined(OPENSSL_SMALL) +#if 0 +/* This code was was of the original submission by Intel and is included here + * under so that it is covered by the ISC license. + * + * Note that this code is still using the (0, 0) form of the point-at-infinity + * so it may not match the current assembly code. */ + +/* Point double: r = 2*a */ +static void ecp_nistz256_point_double(P256_POINT * r, const P256_POINT * a) +{ + BN_ULONG S[P256_LIMBS]; + BN_ULONG M[P256_LIMBS]; + BN_ULONG Zsqr[P256_LIMBS]; + BN_ULONG tmp0[P256_LIMBS]; + + const BN_ULONG *in_x = a->X; + const BN_ULONG *in_y = a->Y; + const BN_ULONG *in_z = a->Z; + + BN_ULONG *res_x = r->X; + BN_ULONG *res_y = r->Y; + BN_ULONG *res_z = r->Z; + + ecp_nistz256_mul_by_2(S, in_y); + + ecp_nistz256_sqr_mont(Zsqr, in_z); + + ecp_nistz256_sqr_mont(S, S); + + ecp_nistz256_mul_mont(res_z, in_z, in_y); + ecp_nistz256_mul_by_2(res_z, res_z); + + ecp_nistz256_add(M, in_x, Zsqr); + ecp_nistz256_sub(Zsqr, in_x, Zsqr); + + ecp_nistz256_sqr_mont(res_y, S); + ecp_nistz256_div_by_2(res_y, res_y); + + ecp_nistz256_mul_mont(M, M, Zsqr); + ecp_nistz256_mul_by_3(M, M); + + ecp_nistz256_mul_mont(S, S, in_x); + ecp_nistz256_mul_by_2(tmp0, S); + + ecp_nistz256_sqr_mont(res_x, M); + + ecp_nistz256_sub(res_x, res_x, tmp0); + ecp_nistz256_sub(S, S, res_x); + + ecp_nistz256_mul_mont(S, S, M); + ecp_nistz256_sub(res_y, S, res_y); +} + +/* Point addition: r = a+b */ +static void ecp_nistz256_point_add(P256_POINT * r, + const P256_POINT * a, const P256_POINT * b) +{ + BN_ULONG U2[P256_LIMBS], S2[P256_LIMBS]; + BN_ULONG U1[P256_LIMBS], S1[P256_LIMBS]; + BN_ULONG Z1sqr[P256_LIMBS]; + BN_ULONG Z2sqr[P256_LIMBS]; + BN_ULONG H[P256_LIMBS], R[P256_LIMBS]; + BN_ULONG Hsqr[P256_LIMBS]; + BN_ULONG Rsqr[P256_LIMBS]; + BN_ULONG Hcub[P256_LIMBS]; + + BN_ULONG res_x[P256_LIMBS]; + BN_ULONG res_y[P256_LIMBS]; + BN_ULONG res_z[P256_LIMBS]; + + BN_ULONG in1infty, in2infty; + + const BN_ULONG *in1_x = a->X; + const BN_ULONG *in1_y = a->Y; + const BN_ULONG *in1_z = a->Z; + + const BN_ULONG *in2_x = b->X; + 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]; + 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]; + + 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) + 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]; + + in1infty = is_zero(in1infty); + in2infty = is_zero(in2infty); + + ecp_nistz256_sqr_mont(Z2sqr, in2_z); /* Z2^2 */ + ecp_nistz256_sqr_mont(Z1sqr, in1_z); /* Z1^2 */ + + ecp_nistz256_mul_mont(S1, Z2sqr, in2_z); /* S1 = Z2^3 */ + ecp_nistz256_mul_mont(S2, Z1sqr, in1_z); /* S2 = Z1^3 */ + + ecp_nistz256_mul_mont(S1, S1, in1_y); /* S1 = Y1*Z2^3 */ + ecp_nistz256_mul_mont(S2, S2, in2_y); /* S2 = Y2*Z1^3 */ + ecp_nistz256_sub(R, S2, S1); /* R = S2 - S1 */ + + ecp_nistz256_mul_mont(U1, in1_x, Z2sqr); /* U1 = X1*Z2^2 */ + ecp_nistz256_mul_mont(U2, in2_x, Z1sqr); /* U2 = X2*Z1^2 */ + ecp_nistz256_sub(H, U2, U1); /* H = U2 - U1 */ + + /* This should not happen during sign/ecdh, + * so no constant time violation */ + if (is_equal(U1, U2) && !in1infty && !in2infty) { + if (is_equal(S1, S2)) { + ecp_nistz256_point_double(r, a); + return; + } else { + memset(r, 0, sizeof(*r)); + return; + } + } + + ecp_nistz256_sqr_mont(Rsqr, R); /* R^2 */ + ecp_nistz256_mul_mont(res_z, H, in1_z); /* Z3 = H*Z1*Z2 */ + ecp_nistz256_sqr_mont(Hsqr, H); /* H^2 */ + ecp_nistz256_mul_mont(res_z, res_z, in2_z); /* Z3 = H*Z1*Z2 */ + ecp_nistz256_mul_mont(Hcub, Hsqr, H); /* H^3 */ + + ecp_nistz256_mul_mont(U2, U1, Hsqr); /* U1*H^2 */ + ecp_nistz256_mul_by_2(Hsqr, U2); /* 2*U1*H^2 */ + + ecp_nistz256_sub(res_x, Rsqr, Hsqr); + ecp_nistz256_sub(res_x, res_x, Hcub); + + ecp_nistz256_sub(res_y, U2, res_x); + + ecp_nistz256_mul_mont(S2, S1, Hcub); + ecp_nistz256_mul_mont(res_y, R, res_y); + ecp_nistz256_sub(res_y, res_y, S2); + + copy_conditional(res_x, in2_x, in1infty); + copy_conditional(res_y, in2_y, in1infty); + copy_conditional(res_z, in2_z, in1infty); + + copy_conditional(res_x, in1_x, in2infty); + copy_conditional(res_y, in1_y, in2infty); + copy_conditional(res_z, in1_z, in2infty); + + memcpy(r->X, res_x, sizeof(res_x)); + memcpy(r->Y, res_y, sizeof(res_y)); + memcpy(r->Z, res_z, sizeof(res_z)); +} + +/* Point addition when b is known to be affine: r = a+b */ +static void ecp_nistz256_point_add_affine(P256_POINT * r, + const P256_POINT * a, + const P256_POINT_AFFINE * b) +{ + BN_ULONG U2[P256_LIMBS], S2[P256_LIMBS]; + BN_ULONG Z1sqr[P256_LIMBS]; + BN_ULONG H[P256_LIMBS], R[P256_LIMBS]; + BN_ULONG Hsqr[P256_LIMBS]; + BN_ULONG Rsqr[P256_LIMBS]; + BN_ULONG Hcub[P256_LIMBS]; + + BN_ULONG res_x[P256_LIMBS]; + BN_ULONG res_y[P256_LIMBS]; + BN_ULONG res_z[P256_LIMBS]; + + BN_ULONG in1infty, in2infty; + + const BN_ULONG *in1_x = a->X; + const BN_ULONG *in1_y = a->Y; + const BN_ULONG *in1_z = a->Z; + + const BN_ULONG *in2_x = b->X; + 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 */ + 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]; + 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]; + + 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) + 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]; + + in1infty = is_zero(in1infty); + in2infty = is_zero(in2infty); + + ecp_nistz256_sqr_mont(Z1sqr, in1_z); /* Z1^2 */ + + ecp_nistz256_mul_mont(U2, in2_x, Z1sqr); /* U2 = X2*Z1^2 */ + ecp_nistz256_sub(H, U2, in1_x); /* H = U2 - U1 */ + + ecp_nistz256_mul_mont(S2, Z1sqr, in1_z); /* S2 = Z1^3 */ + + ecp_nistz256_mul_mont(res_z, H, in1_z); /* Z3 = H*Z1*Z2 */ + + ecp_nistz256_mul_mont(S2, S2, in2_y); /* S2 = Y2*Z1^3 */ + ecp_nistz256_sub(R, S2, in1_y); /* R = S2 - S1 */ + + ecp_nistz256_sqr_mont(Hsqr, H); /* H^2 */ + ecp_nistz256_sqr_mont(Rsqr, R); /* R^2 */ + ecp_nistz256_mul_mont(Hcub, Hsqr, H); /* H^3 */ + + ecp_nistz256_mul_mont(U2, in1_x, Hsqr); /* U1*H^2 */ + ecp_nistz256_mul_by_2(Hsqr, U2); /* 2*U1*H^2 */ + + ecp_nistz256_sub(res_x, Rsqr, Hsqr); + ecp_nistz256_sub(res_x, res_x, Hcub); + ecp_nistz256_sub(H, U2, res_x); + + ecp_nistz256_mul_mont(S2, in1_y, Hcub); + ecp_nistz256_mul_mont(H, H, R); + ecp_nistz256_sub(res_y, H, S2); + + copy_conditional(res_x, in2_x, in1infty); + copy_conditional(res_x, in1_x, in2infty); + + copy_conditional(res_y, in2_y, in1infty); + copy_conditional(res_y, in1_y, in2infty); + + copy_conditional(res_z, ONE, in1infty); + copy_conditional(res_z, in1_z, in2infty); + + memcpy(r->X, res_x, sizeof(res_x)); + memcpy(r->Y, res_y, sizeof(res_y)); + memcpy(r->Z, res_z, sizeof(res_z)); +} +#endif + typedef P256_POINT_AFFINE PRECOMP256_ROW[64]; /* One converted into the Montgomery domain */