[PATCH 1/2] Revert "lib/mpi: Introduce ec implementation to MPI library"

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This reverts commit d58bb7e55a8a65894cc02f27c3e2bf9403e7c40f.

It's no longer needed since sm2 has been removed.

Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
---
 include/linux/mpi.h     |  105 ---
 lib/crypto/mpi/Makefile |    1 -
 lib/crypto/mpi/ec.c     | 1507 ---------------------------------------
 3 files changed, 1613 deletions(-)
 delete mode 100644 lib/crypto/mpi/ec.c

diff --git a/include/linux/mpi.h b/include/linux/mpi.h
index eb0d1c1db208..89b720893e12 100644
--- a/include/linux/mpi.h
+++ b/include/linux/mpi.h
@@ -157,111 +157,6 @@ void mpi_fdiv_q(MPI quot, MPI dividend, MPI divisor);
 /*-- mpi-inv.c --*/
 int mpi_invm(MPI x, MPI a, MPI n);
 
-/*-- ec.c --*/
-
-/* Object to represent a point in projective coordinates */
-struct gcry_mpi_point {
-	MPI x;
-	MPI y;
-	MPI z;
-};
-
-typedef struct gcry_mpi_point *MPI_POINT;
-
-/* Models describing an elliptic curve */
-enum gcry_mpi_ec_models {
-	/* The Short Weierstrass equation is
-	 *      y^2 = x^3 + ax + b
-	 */
-	MPI_EC_WEIERSTRASS = 0,
-	/* The Montgomery equation is
-	 *      by^2 = x^3 + ax^2 + x
-	 */
-	MPI_EC_MONTGOMERY,
-	/* The Twisted Edwards equation is
-	 *      ax^2 + y^2 = 1 + bx^2y^2
-	 * Note that we use 'b' instead of the commonly used 'd'.
-	 */
-	MPI_EC_EDWARDS
-};
-
-/* Dialects used with elliptic curves */
-enum ecc_dialects {
-	ECC_DIALECT_STANDARD = 0,
-	ECC_DIALECT_ED25519,
-	ECC_DIALECT_SAFECURVE
-};
-
-/* This context is used with all our EC functions. */
-struct mpi_ec_ctx {
-	enum gcry_mpi_ec_models model; /* The model describing this curve. */
-	enum ecc_dialects dialect;     /* The ECC dialect used with the curve. */
-	int flags;                     /* Public key flags (not always used). */
-	unsigned int nbits;            /* Number of bits.  */
-
-	/* Domain parameters.  Note that they may not all be set and if set
-	 * the MPIs may be flagged as constant.
-	 */
-	MPI p;         /* Prime specifying the field GF(p).  */
-	MPI a;         /* First coefficient of the Weierstrass equation.  */
-	MPI b;         /* Second coefficient of the Weierstrass equation.  */
-	MPI_POINT G;   /* Base point (generator).  */
-	MPI n;         /* Order of G.  */
-	unsigned int h;       /* Cofactor.  */
-
-	/* The actual key.  May not be set.  */
-	MPI_POINT Q;   /* Public key.   */
-	MPI d;         /* Private key.  */
-
-	const char *name;      /* Name of the curve.  */
-
-	/* This structure is private to mpi/ec.c! */
-	struct {
-		struct {
-			unsigned int a_is_pminus3:1;
-			unsigned int two_inv_p:1;
-		} valid; /* Flags to help setting the helper vars below.  */
-
-		int a_is_pminus3;  /* True if A = P - 3. */
-
-		MPI two_inv_p;
-
-		mpi_barrett_t p_barrett;
-
-		/* Scratch variables.  */
-		MPI scratch[11];
-
-		/* Helper for fast reduction.  */
-		/*   int nist_nbits; /\* If this is a NIST curve, the # of bits. *\/ */
-		/*   MPI s[10]; */
-		/*   MPI c; */
-	} t;
-
-	/* Curve specific computation routines for the field.  */
-	void (*addm)(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx);
-	void (*subm)(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ec);
-	void (*mulm)(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx);
-	void (*pow2)(MPI w, const MPI b, struct mpi_ec_ctx *ctx);
-	void (*mul2)(MPI w, MPI u, struct mpi_ec_ctx *ctx);
-};
-
-void mpi_ec_init(struct mpi_ec_ctx *ctx, enum gcry_mpi_ec_models model,
-			enum ecc_dialects dialect,
-			int flags, MPI p, MPI a, MPI b);
-void mpi_ec_deinit(struct mpi_ec_ctx *ctx);
-MPI_POINT mpi_point_new(unsigned int nbits);
-void mpi_point_release(MPI_POINT p);
-void mpi_point_init(MPI_POINT p);
-void mpi_point_free_parts(MPI_POINT p);
-int mpi_ec_get_affine(MPI x, MPI y, MPI_POINT point, struct mpi_ec_ctx *ctx);
-void mpi_ec_add_points(MPI_POINT result,
-			MPI_POINT p1, MPI_POINT p2,
-			struct mpi_ec_ctx *ctx);
-void mpi_ec_mul_point(MPI_POINT result,
-			MPI scalar, MPI_POINT point,
-			struct mpi_ec_ctx *ctx);
-int mpi_ec_curve_point(MPI_POINT point, struct mpi_ec_ctx *ctx);
-
 /* inline functions */
 
 /**
diff --git a/lib/crypto/mpi/Makefile b/lib/crypto/mpi/Makefile
index 6e6ef9a34fe1..477debd7ed50 100644
--- a/lib/crypto/mpi/Makefile
+++ b/lib/crypto/mpi/Makefile
@@ -13,7 +13,6 @@ mpi-y = \
 	generic_mpih-rshift.o		\
 	generic_mpih-sub1.o		\
 	generic_mpih-add1.o		\
-	ec.o				\
 	mpicoder.o			\
 	mpi-add.o			\
 	mpi-bit.o			\
diff --git a/lib/crypto/mpi/ec.c b/lib/crypto/mpi/ec.c
deleted file mode 100644
index 4781f00982ef..000000000000
--- a/lib/crypto/mpi/ec.c
+++ /dev/null
@@ -1,1507 +0,0 @@
-/* ec.c -  Elliptic Curve functions
- * Copyright (C) 2007 Free Software Foundation, Inc.
- * Copyright (C) 2013 g10 Code GmbH
- *
- * This file is part of Libgcrypt.
- *
- * Libgcrypt is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Lesser General Public License as
- * published by the Free Software Foundation; either version 2.1 of
- * the License, or (at your option) any later version.
- *
- * Libgcrypt is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this program; if not, see <http://www.gnu.org/licenses/>.
- */
-
-#include "mpi-internal.h"
-#include "longlong.h"
-
-#define point_init(a)  mpi_point_init((a))
-#define point_free(a)  mpi_point_free_parts((a))
-
-#define log_error(fmt, ...) pr_err(fmt, ##__VA_ARGS__)
-#define log_fatal(fmt, ...) pr_err(fmt, ##__VA_ARGS__)
-
-#define DIM(v) (sizeof(v)/sizeof((v)[0]))
-
-
-/* Create a new point option.  NBITS gives the size in bits of one
- * coordinate; it is only used to pre-allocate some resources and
- * might also be passed as 0 to use a default value.
- */
-MPI_POINT mpi_point_new(unsigned int nbits)
-{
-	MPI_POINT p;
-
-	(void)nbits;  /* Currently not used.  */
-
-	p = kmalloc(sizeof(*p), GFP_KERNEL);
-	if (p)
-		mpi_point_init(p);
-	return p;
-}
-EXPORT_SYMBOL_GPL(mpi_point_new);
-
-/* Release the point object P.  P may be NULL. */
-void mpi_point_release(MPI_POINT p)
-{
-	if (p) {
-		mpi_point_free_parts(p);
-		kfree(p);
-	}
-}
-EXPORT_SYMBOL_GPL(mpi_point_release);
-
-/* Initialize the fields of a point object.  gcry_mpi_point_free_parts
- * may be used to release the fields.
- */
-void mpi_point_init(MPI_POINT p)
-{
-	p->x = mpi_new(0);
-	p->y = mpi_new(0);
-	p->z = mpi_new(0);
-}
-EXPORT_SYMBOL_GPL(mpi_point_init);
-
-/* Release the parts of a point object. */
-void mpi_point_free_parts(MPI_POINT p)
-{
-	mpi_free(p->x); p->x = NULL;
-	mpi_free(p->y); p->y = NULL;
-	mpi_free(p->z); p->z = NULL;
-}
-EXPORT_SYMBOL_GPL(mpi_point_free_parts);
-
-/* Set the value from S into D.  */
-static void point_set(MPI_POINT d, MPI_POINT s)
-{
-	mpi_set(d->x, s->x);
-	mpi_set(d->y, s->y);
-	mpi_set(d->z, s->z);
-}
-
-static void point_resize(MPI_POINT p, struct mpi_ec_ctx *ctx)
-{
-	size_t nlimbs = ctx->p->nlimbs;
-
-	mpi_resize(p->x, nlimbs);
-	p->x->nlimbs = nlimbs;
-	mpi_resize(p->z, nlimbs);
-	p->z->nlimbs = nlimbs;
-
-	if (ctx->model != MPI_EC_MONTGOMERY) {
-		mpi_resize(p->y, nlimbs);
-		p->y->nlimbs = nlimbs;
-	}
-}
-
-static void point_swap_cond(MPI_POINT d, MPI_POINT s, unsigned long swap,
-		struct mpi_ec_ctx *ctx)
-{
-	mpi_swap_cond(d->x, s->x, swap);
-	if (ctx->model != MPI_EC_MONTGOMERY)
-		mpi_swap_cond(d->y, s->y, swap);
-	mpi_swap_cond(d->z, s->z, swap);
-}
-
-
-/* W = W mod P.  */
-static void ec_mod(MPI w, struct mpi_ec_ctx *ec)
-{
-	if (ec->t.p_barrett)
-		mpi_mod_barrett(w, w, ec->t.p_barrett);
-	else
-		mpi_mod(w, w, ec->p);
-}
-
-static void ec_addm(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx)
-{
-	mpi_add(w, u, v);
-	ec_mod(w, ctx);
-}
-
-static void ec_subm(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ec)
-{
-	mpi_sub(w, u, v);
-	while (w->sign)
-		mpi_add(w, w, ec->p);
-	/*ec_mod(w, ec);*/
-}
-
-static void ec_mulm(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx)
-{
-	mpi_mul(w, u, v);
-	ec_mod(w, ctx);
-}
-
-/* W = 2 * U mod P.  */
-static void ec_mul2(MPI w, MPI u, struct mpi_ec_ctx *ctx)
-{
-	mpi_lshift(w, u, 1);
-	ec_mod(w, ctx);
-}
-
-static void ec_powm(MPI w, const MPI b, const MPI e,
-		struct mpi_ec_ctx *ctx)
-{
-	mpi_powm(w, b, e, ctx->p);
-	/* mpi_abs(w); */
-}
-
-/* Shortcut for
- * ec_powm(B, B, mpi_const(MPI_C_TWO), ctx);
- * for easier optimization.
- */
-static void ec_pow2(MPI w, const MPI b, struct mpi_ec_ctx *ctx)
-{
-	/* Using mpi_mul is slightly faster (at least on amd64).  */
-	/* mpi_powm(w, b, mpi_const(MPI_C_TWO), ctx->p); */
-	ec_mulm(w, b, b, ctx);
-}
-
-/* Shortcut for
- * ec_powm(B, B, mpi_const(MPI_C_THREE), ctx);
- * for easier optimization.
- */
-static void ec_pow3(MPI w, const MPI b, struct mpi_ec_ctx *ctx)
-{
-	mpi_powm(w, b, mpi_const(MPI_C_THREE), ctx->p);
-}
-
-static void ec_invm(MPI x, MPI a, struct mpi_ec_ctx *ctx)
-{
-	if (!mpi_invm(x, a, ctx->p))
-		log_error("ec_invm: inverse does not exist:\n");
-}
-
-static void mpih_set_cond(mpi_ptr_t wp, mpi_ptr_t up,
-		mpi_size_t usize, unsigned long set)
-{
-	mpi_size_t i;
-	mpi_limb_t mask = ((mpi_limb_t)0) - set;
-	mpi_limb_t x;
-
-	for (i = 0; i < usize; i++) {
-		x = mask & (wp[i] ^ up[i]);
-		wp[i] = wp[i] ^ x;
-	}
-}
-
-/* Routines for 2^255 - 19.  */
-
-#define LIMB_SIZE_25519 ((256+BITS_PER_MPI_LIMB-1)/BITS_PER_MPI_LIMB)
-
-static void ec_addm_25519(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx)
-{
-	mpi_ptr_t wp, up, vp;
-	mpi_size_t wsize = LIMB_SIZE_25519;
-	mpi_limb_t n[LIMB_SIZE_25519];
-	mpi_limb_t borrow;
-
-	if (w->nlimbs != wsize || u->nlimbs != wsize || v->nlimbs != wsize)
-		log_bug("addm_25519: different sizes\n");
-
-	memset(n, 0, sizeof(n));
-	up = u->d;
-	vp = v->d;
-	wp = w->d;
-
-	mpihelp_add_n(wp, up, vp, wsize);
-	borrow = mpihelp_sub_n(wp, wp, ctx->p->d, wsize);
-	mpih_set_cond(n, ctx->p->d, wsize, (borrow != 0UL));
-	mpihelp_add_n(wp, wp, n, wsize);
-	wp[LIMB_SIZE_25519-1] &= ~((mpi_limb_t)1 << (255 % BITS_PER_MPI_LIMB));
-}
-
-static void ec_subm_25519(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx)
-{
-	mpi_ptr_t wp, up, vp;
-	mpi_size_t wsize = LIMB_SIZE_25519;
-	mpi_limb_t n[LIMB_SIZE_25519];
-	mpi_limb_t borrow;
-
-	if (w->nlimbs != wsize || u->nlimbs != wsize || v->nlimbs != wsize)
-		log_bug("subm_25519: different sizes\n");
-
-	memset(n, 0, sizeof(n));
-	up = u->d;
-	vp = v->d;
-	wp = w->d;
-
-	borrow = mpihelp_sub_n(wp, up, vp, wsize);
-	mpih_set_cond(n, ctx->p->d, wsize, (borrow != 0UL));
-	mpihelp_add_n(wp, wp, n, wsize);
-	wp[LIMB_SIZE_25519-1] &= ~((mpi_limb_t)1 << (255 % BITS_PER_MPI_LIMB));
-}
-
-static void ec_mulm_25519(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx)
-{
-	mpi_ptr_t wp, up, vp;
-	mpi_size_t wsize = LIMB_SIZE_25519;
-	mpi_limb_t n[LIMB_SIZE_25519*2];
-	mpi_limb_t m[LIMB_SIZE_25519+1];
-	mpi_limb_t cy;
-	int msb;
-
-	(void)ctx;
-	if (w->nlimbs != wsize || u->nlimbs != wsize || v->nlimbs != wsize)
-		log_bug("mulm_25519: different sizes\n");
-
-	up = u->d;
-	vp = v->d;
-	wp = w->d;
-
-	mpihelp_mul_n(n, up, vp, wsize);
-	memcpy(wp, n, wsize * BYTES_PER_MPI_LIMB);
-	wp[LIMB_SIZE_25519-1] &= ~((mpi_limb_t)1 << (255 % BITS_PER_MPI_LIMB));
-
-	memcpy(m, n+LIMB_SIZE_25519-1, (wsize+1) * BYTES_PER_MPI_LIMB);
-	mpihelp_rshift(m, m, LIMB_SIZE_25519+1, (255 % BITS_PER_MPI_LIMB));
-
-	memcpy(n, m, wsize * BYTES_PER_MPI_LIMB);
-	cy = mpihelp_lshift(m, m, LIMB_SIZE_25519, 4);
-	m[LIMB_SIZE_25519] = cy;
-	cy = mpihelp_add_n(m, m, n, wsize);
-	m[LIMB_SIZE_25519] += cy;
-	cy = mpihelp_add_n(m, m, n, wsize);
-	m[LIMB_SIZE_25519] += cy;
-	cy = mpihelp_add_n(m, m, n, wsize);
-	m[LIMB_SIZE_25519] += cy;
-
-	cy = mpihelp_add_n(wp, wp, m, wsize);
-	m[LIMB_SIZE_25519] += cy;
-
-	memset(m, 0, wsize * BYTES_PER_MPI_LIMB);
-	msb = (wp[LIMB_SIZE_25519-1] >> (255 % BITS_PER_MPI_LIMB));
-	m[0] = (m[LIMB_SIZE_25519] * 2 + msb) * 19;
-	wp[LIMB_SIZE_25519-1] &= ~((mpi_limb_t)1 << (255 % BITS_PER_MPI_LIMB));
-	mpihelp_add_n(wp, wp, m, wsize);
-
-	m[0] = 0;
-	cy = mpihelp_sub_n(wp, wp, ctx->p->d, wsize);
-	mpih_set_cond(m, ctx->p->d, wsize, (cy != 0UL));
-	mpihelp_add_n(wp, wp, m, wsize);
-}
-
-static void ec_mul2_25519(MPI w, MPI u, struct mpi_ec_ctx *ctx)
-{
-	ec_addm_25519(w, u, u, ctx);
-}
-
-static void ec_pow2_25519(MPI w, const MPI b, struct mpi_ec_ctx *ctx)
-{
-	ec_mulm_25519(w, b, b, ctx);
-}
-
-/* Routines for 2^448 - 2^224 - 1.  */
-
-#define LIMB_SIZE_448 ((448+BITS_PER_MPI_LIMB-1)/BITS_PER_MPI_LIMB)
-#define LIMB_SIZE_HALF_448 ((LIMB_SIZE_448+1)/2)
-
-static void ec_addm_448(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx)
-{
-	mpi_ptr_t wp, up, vp;
-	mpi_size_t wsize = LIMB_SIZE_448;
-	mpi_limb_t n[LIMB_SIZE_448];
-	mpi_limb_t cy;
-
-	if (w->nlimbs != wsize || u->nlimbs != wsize || v->nlimbs != wsize)
-		log_bug("addm_448: different sizes\n");
-
-	memset(n, 0, sizeof(n));
-	up = u->d;
-	vp = v->d;
-	wp = w->d;
-
-	cy = mpihelp_add_n(wp, up, vp, wsize);
-	mpih_set_cond(n, ctx->p->d, wsize, (cy != 0UL));
-	mpihelp_sub_n(wp, wp, n, wsize);
-}
-
-static void ec_subm_448(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx)
-{
-	mpi_ptr_t wp, up, vp;
-	mpi_size_t wsize = LIMB_SIZE_448;
-	mpi_limb_t n[LIMB_SIZE_448];
-	mpi_limb_t borrow;
-
-	if (w->nlimbs != wsize || u->nlimbs != wsize || v->nlimbs != wsize)
-		log_bug("subm_448: different sizes\n");
-
-	memset(n, 0, sizeof(n));
-	up = u->d;
-	vp = v->d;
-	wp = w->d;
-
-	borrow = mpihelp_sub_n(wp, up, vp, wsize);
-	mpih_set_cond(n, ctx->p->d, wsize, (borrow != 0UL));
-	mpihelp_add_n(wp, wp, n, wsize);
-}
-
-static void ec_mulm_448(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx)
-{
-	mpi_ptr_t wp, up, vp;
-	mpi_size_t wsize = LIMB_SIZE_448;
-	mpi_limb_t n[LIMB_SIZE_448*2];
-	mpi_limb_t a2[LIMB_SIZE_HALF_448];
-	mpi_limb_t a3[LIMB_SIZE_HALF_448];
-	mpi_limb_t b0[LIMB_SIZE_HALF_448];
-	mpi_limb_t b1[LIMB_SIZE_HALF_448];
-	mpi_limb_t cy;
-	int i;
-#if (LIMB_SIZE_HALF_448 > LIMB_SIZE_448/2)
-	mpi_limb_t b1_rest, a3_rest;
-#endif
-
-	if (w->nlimbs != wsize || u->nlimbs != wsize || v->nlimbs != wsize)
-		log_bug("mulm_448: different sizes\n");
-
-	up = u->d;
-	vp = v->d;
-	wp = w->d;
-
-	mpihelp_mul_n(n, up, vp, wsize);
-
-	for (i = 0; i < (wsize + 1) / 2; i++) {
-		b0[i] = n[i];
-		b1[i] = n[i+wsize/2];
-		a2[i] = n[i+wsize];
-		a3[i] = n[i+wsize+wsize/2];
-	}
-
-#if (LIMB_SIZE_HALF_448 > LIMB_SIZE_448/2)
-	b0[LIMB_SIZE_HALF_448-1] &= ((mpi_limb_t)1UL << 32)-1;
-	a2[LIMB_SIZE_HALF_448-1] &= ((mpi_limb_t)1UL << 32)-1;
-
-	b1_rest = 0;
-	a3_rest = 0;
-
-	for (i = (wsize + 1) / 2 - 1; i >= 0; i--) {
-		mpi_limb_t b1v, a3v;
-		b1v = b1[i];
-		a3v = a3[i];
-		b1[i] = (b1_rest << 32) | (b1v >> 32);
-		a3[i] = (a3_rest << 32) | (a3v >> 32);
-		b1_rest = b1v & (((mpi_limb_t)1UL << 32)-1);
-		a3_rest = a3v & (((mpi_limb_t)1UL << 32)-1);
-	}
-#endif
-
-	cy = mpihelp_add_n(b0, b0, a2, LIMB_SIZE_HALF_448);
-	cy += mpihelp_add_n(b0, b0, a3, LIMB_SIZE_HALF_448);
-	for (i = 0; i < (wsize + 1) / 2; i++)
-		wp[i] = b0[i];
-#if (LIMB_SIZE_HALF_448 > LIMB_SIZE_448/2)
-	wp[LIMB_SIZE_HALF_448-1] &= (((mpi_limb_t)1UL << 32)-1);
-#endif
-
-#if (LIMB_SIZE_HALF_448 > LIMB_SIZE_448/2)
-	cy = b0[LIMB_SIZE_HALF_448-1] >> 32;
-#endif
-
-	cy = mpihelp_add_1(b1, b1, LIMB_SIZE_HALF_448, cy);
-	cy += mpihelp_add_n(b1, b1, a2, LIMB_SIZE_HALF_448);
-	cy += mpihelp_add_n(b1, b1, a3, LIMB_SIZE_HALF_448);
-	cy += mpihelp_add_n(b1, b1, a3, LIMB_SIZE_HALF_448);
-#if (LIMB_SIZE_HALF_448 > LIMB_SIZE_448/2)
-	b1_rest = 0;
-	for (i = (wsize + 1) / 2 - 1; i >= 0; i--) {
-		mpi_limb_t b1v = b1[i];
-		b1[i] = (b1_rest << 32) | (b1v >> 32);
-		b1_rest = b1v & (((mpi_limb_t)1UL << 32)-1);
-	}
-	wp[LIMB_SIZE_HALF_448-1] |= (b1_rest << 32);
-#endif
-	for (i = 0; i < wsize / 2; i++)
-		wp[i+(wsize + 1) / 2] = b1[i];
-
-#if (LIMB_SIZE_HALF_448 > LIMB_SIZE_448/2)
-	cy = b1[LIMB_SIZE_HALF_448-1];
-#endif
-
-	memset(n, 0, wsize * BYTES_PER_MPI_LIMB);
-
-#if (LIMB_SIZE_HALF_448 > LIMB_SIZE_448/2)
-	n[LIMB_SIZE_HALF_448-1] = cy << 32;
-#else
-	n[LIMB_SIZE_HALF_448] = cy;
-#endif
-	n[0] = cy;
-	mpihelp_add_n(wp, wp, n, wsize);
-
-	memset(n, 0, wsize * BYTES_PER_MPI_LIMB);
-	cy = mpihelp_sub_n(wp, wp, ctx->p->d, wsize);
-	mpih_set_cond(n, ctx->p->d, wsize, (cy != 0UL));
-	mpihelp_add_n(wp, wp, n, wsize);
-}
-
-static void ec_mul2_448(MPI w, MPI u, struct mpi_ec_ctx *ctx)
-{
-	ec_addm_448(w, u, u, ctx);
-}
-
-static void ec_pow2_448(MPI w, const MPI b, struct mpi_ec_ctx *ctx)
-{
-	ec_mulm_448(w, b, b, ctx);
-}
-
-struct field_table {
-	const char *p;
-
-	/* computation routines for the field.  */
-	void (*addm)(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx);
-	void (*subm)(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx);
-	void (*mulm)(MPI w, MPI u, MPI v, struct mpi_ec_ctx *ctx);
-	void (*mul2)(MPI w, MPI u, struct mpi_ec_ctx *ctx);
-	void (*pow2)(MPI w, const MPI b, struct mpi_ec_ctx *ctx);
-};
-
-static const struct field_table field_table[] = {
-	{
-		"0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFED",
-		ec_addm_25519,
-		ec_subm_25519,
-		ec_mulm_25519,
-		ec_mul2_25519,
-		ec_pow2_25519
-	},
-	{
-		"0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFE"
-		"FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF",
-		ec_addm_448,
-		ec_subm_448,
-		ec_mulm_448,
-		ec_mul2_448,
-		ec_pow2_448
-	},
-	{ NULL, NULL, NULL, NULL, NULL, NULL },
-};
-
-/* Force recomputation of all helper variables.  */
-static void mpi_ec_get_reset(struct mpi_ec_ctx *ec)
-{
-	ec->t.valid.a_is_pminus3 = 0;
-	ec->t.valid.two_inv_p = 0;
-}
-
-/* Accessor for helper variable.  */
-static int ec_get_a_is_pminus3(struct mpi_ec_ctx *ec)
-{
-	MPI tmp;
-
-	if (!ec->t.valid.a_is_pminus3) {
-		ec->t.valid.a_is_pminus3 = 1;
-		tmp = mpi_alloc_like(ec->p);
-		mpi_sub_ui(tmp, ec->p, 3);
-		ec->t.a_is_pminus3 = !mpi_cmp(ec->a, tmp);
-		mpi_free(tmp);
-	}
-
-	return ec->t.a_is_pminus3;
-}
-
-/* Accessor for helper variable.  */
-static MPI ec_get_two_inv_p(struct mpi_ec_ctx *ec)
-{
-	if (!ec->t.valid.two_inv_p) {
-		ec->t.valid.two_inv_p = 1;
-		if (!ec->t.two_inv_p)
-			ec->t.two_inv_p = mpi_alloc(0);
-		ec_invm(ec->t.two_inv_p, mpi_const(MPI_C_TWO), ec);
-	}
-	return ec->t.two_inv_p;
-}
-
-static const char *const curve25519_bad_points[] = {
-	"0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffed",
-	"0x0000000000000000000000000000000000000000000000000000000000000000",
-	"0x0000000000000000000000000000000000000000000000000000000000000001",
-	"0x00b8495f16056286fdb1329ceb8d09da6ac49ff1fae35616aeb8413b7c7aebe0",
-	"0x57119fd0dd4e22d8868e1c58c45c44045bef839c55b1d0b1248c50a3bc959c5f",
-	"0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffec",
-	"0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffee",
-	NULL
-};
-
-static const char *const curve448_bad_points[] = {
-	"0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffe"
-	"ffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
-	"0x00000000000000000000000000000000000000000000000000000000"
-	"00000000000000000000000000000000000000000000000000000000",
-	"0x00000000000000000000000000000000000000000000000000000000"
-	"00000000000000000000000000000000000000000000000000000001",
-	"0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffe"
-	"fffffffffffffffffffffffffffffffffffffffffffffffffffffffe",
-	"0xffffffffffffffffffffffffffffffffffffffffffffffffffffffff"
-	"00000000000000000000000000000000000000000000000000000000",
-	NULL
-};
-
-static const char *const *bad_points_table[] = {
-	curve25519_bad_points,
-	curve448_bad_points,
-};
-
-static void mpi_ec_coefficient_normalize(MPI a, MPI p)
-{
-	if (a->sign) {
-		mpi_resize(a, p->nlimbs);
-		mpihelp_sub_n(a->d, p->d, a->d, p->nlimbs);
-		a->nlimbs = p->nlimbs;
-		a->sign = 0;
-	}
-}
-
-/* This function initialized a context for elliptic curve based on the
- * field GF(p).  P is the prime specifying this field, A is the first
- * coefficient.  CTX is expected to be zeroized.
- */
-void mpi_ec_init(struct mpi_ec_ctx *ctx, enum gcry_mpi_ec_models model,
-			enum ecc_dialects dialect,
-			int flags, MPI p, MPI a, MPI b)
-{
-	int i;
-	static int use_barrett = -1 /* TODO: 1 or -1 */;
-
-	mpi_ec_coefficient_normalize(a, p);
-	mpi_ec_coefficient_normalize(b, p);
-
-	/* Fixme: Do we want to check some constraints? e.g.  a < p  */
-
-	ctx->model = model;
-	ctx->dialect = dialect;
-	ctx->flags = flags;
-	if (dialect == ECC_DIALECT_ED25519)
-		ctx->nbits = 256;
-	else
-		ctx->nbits = mpi_get_nbits(p);
-	ctx->p = mpi_copy(p);
-	ctx->a = mpi_copy(a);
-	ctx->b = mpi_copy(b);
-
-	ctx->d = NULL;
-	ctx->t.two_inv_p = NULL;
-
-	ctx->t.p_barrett = use_barrett > 0 ? mpi_barrett_init(ctx->p, 0) : NULL;
-
-	mpi_ec_get_reset(ctx);
-
-	if (model == MPI_EC_MONTGOMERY) {
-		for (i = 0; i < DIM(bad_points_table); i++) {
-			MPI p_candidate = mpi_scanval(bad_points_table[i][0]);
-			int match_p = !mpi_cmp(ctx->p, p_candidate);
-			int j;
-
-			mpi_free(p_candidate);
-			if (!match_p)
-				continue;
-
-			for (j = 0; i < DIM(ctx->t.scratch) && bad_points_table[i][j]; j++)
-				ctx->t.scratch[j] = mpi_scanval(bad_points_table[i][j]);
-		}
-	} else {
-		/* Allocate scratch variables.  */
-		for (i = 0; i < DIM(ctx->t.scratch); i++)
-			ctx->t.scratch[i] = mpi_alloc_like(ctx->p);
-	}
-
-	ctx->addm = ec_addm;
-	ctx->subm = ec_subm;
-	ctx->mulm = ec_mulm;
-	ctx->mul2 = ec_mul2;
-	ctx->pow2 = ec_pow2;
-
-	for (i = 0; field_table[i].p; i++) {
-		MPI f_p;
-
-		f_p = mpi_scanval(field_table[i].p);
-		if (!f_p)
-			break;
-
-		if (!mpi_cmp(p, f_p)) {
-			ctx->addm = field_table[i].addm;
-			ctx->subm = field_table[i].subm;
-			ctx->mulm = field_table[i].mulm;
-			ctx->mul2 = field_table[i].mul2;
-			ctx->pow2 = field_table[i].pow2;
-			mpi_free(f_p);
-
-			mpi_resize(ctx->a, ctx->p->nlimbs);
-			ctx->a->nlimbs = ctx->p->nlimbs;
-
-			mpi_resize(ctx->b, ctx->p->nlimbs);
-			ctx->b->nlimbs = ctx->p->nlimbs;
-
-			for (i = 0; i < DIM(ctx->t.scratch) && ctx->t.scratch[i]; i++)
-				ctx->t.scratch[i]->nlimbs = ctx->p->nlimbs;
-
-			break;
-		}
-
-		mpi_free(f_p);
-	}
-}
-EXPORT_SYMBOL_GPL(mpi_ec_init);
-
-void mpi_ec_deinit(struct mpi_ec_ctx *ctx)
-{
-	int i;
-
-	mpi_barrett_free(ctx->t.p_barrett);
-
-	/* Domain parameter.  */
-	mpi_free(ctx->p);
-	mpi_free(ctx->a);
-	mpi_free(ctx->b);
-	mpi_point_release(ctx->G);
-	mpi_free(ctx->n);
-
-	/* The key.  */
-	mpi_point_release(ctx->Q);
-	mpi_free(ctx->d);
-
-	/* Private data of ec.c.  */
-	mpi_free(ctx->t.two_inv_p);
-
-	for (i = 0; i < DIM(ctx->t.scratch); i++)
-		mpi_free(ctx->t.scratch[i]);
-}
-EXPORT_SYMBOL_GPL(mpi_ec_deinit);
-
-/* Compute the affine coordinates from the projective coordinates in
- * POINT.  Set them into X and Y.  If one coordinate is not required,
- * X or Y may be passed as NULL.  CTX is the usual context. Returns: 0
- * on success or !0 if POINT is at infinity.
- */
-int mpi_ec_get_affine(MPI x, MPI y, MPI_POINT point, struct mpi_ec_ctx *ctx)
-{
-	if (!mpi_cmp_ui(point->z, 0))
-		return -1;
-
-	switch (ctx->model) {
-	case MPI_EC_WEIERSTRASS: /* Using Jacobian coordinates.  */
-		{
-			MPI z1, z2, z3;
-
-			z1 = mpi_new(0);
-			z2 = mpi_new(0);
-			ec_invm(z1, point->z, ctx);  /* z1 = z^(-1) mod p  */
-			ec_mulm(z2, z1, z1, ctx);    /* z2 = z^(-2) mod p  */
-
-			if (x)
-				ec_mulm(x, point->x, z2, ctx);
-
-			if (y) {
-				z3 = mpi_new(0);
-				ec_mulm(z3, z2, z1, ctx);      /* z3 = z^(-3) mod p */
-				ec_mulm(y, point->y, z3, ctx);
-				mpi_free(z3);
-			}
-
-			mpi_free(z2);
-			mpi_free(z1);
-		}
-		return 0;
-
-	case MPI_EC_MONTGOMERY:
-		{
-			if (x)
-				mpi_set(x, point->x);
-
-			if (y) {
-				log_fatal("%s: Getting Y-coordinate on %s is not supported\n",
-						"mpi_ec_get_affine", "Montgomery");
-				return -1;
-			}
-		}
-		return 0;
-
-	case MPI_EC_EDWARDS:
-		{
-			MPI z;
-
-			z = mpi_new(0);
-			ec_invm(z, point->z, ctx);
-
-			mpi_resize(z, ctx->p->nlimbs);
-			z->nlimbs = ctx->p->nlimbs;
-
-			if (x) {
-				mpi_resize(x, ctx->p->nlimbs);
-				x->nlimbs = ctx->p->nlimbs;
-				ctx->mulm(x, point->x, z, ctx);
-			}
-			if (y) {
-				mpi_resize(y, ctx->p->nlimbs);
-				y->nlimbs = ctx->p->nlimbs;
-				ctx->mulm(y, point->y, z, ctx);
-			}
-
-			mpi_free(z);
-		}
-		return 0;
-
-	default:
-		return -1;
-	}
-}
-EXPORT_SYMBOL_GPL(mpi_ec_get_affine);
-
-/*  RESULT = 2 * POINT  (Weierstrass version). */
-static void dup_point_weierstrass(MPI_POINT result,
-		MPI_POINT point, struct mpi_ec_ctx *ctx)
-{
-#define x3 (result->x)
-#define y3 (result->y)
-#define z3 (result->z)
-#define t1 (ctx->t.scratch[0])
-#define t2 (ctx->t.scratch[1])
-#define t3 (ctx->t.scratch[2])
-#define l1 (ctx->t.scratch[3])
-#define l2 (ctx->t.scratch[4])
-#define l3 (ctx->t.scratch[5])
-
-	if (!mpi_cmp_ui(point->y, 0) || !mpi_cmp_ui(point->z, 0)) {
-		/* P_y == 0 || P_z == 0 => [1:1:0] */
-		mpi_set_ui(x3, 1);
-		mpi_set_ui(y3, 1);
-		mpi_set_ui(z3, 0);
-	} else {
-		if (ec_get_a_is_pminus3(ctx)) {
-			/* Use the faster case.  */
-			/* L1 = 3(X - Z^2)(X + Z^2) */
-			/*                          T1: used for Z^2. */
-			/*                          T2: used for the right term. */
-			ec_pow2(t1, point->z, ctx);
-			ec_subm(l1, point->x, t1, ctx);
-			ec_mulm(l1, l1, mpi_const(MPI_C_THREE), ctx);
-			ec_addm(t2, point->x, t1, ctx);
-			ec_mulm(l1, l1, t2, ctx);
-		} else {
-			/* Standard case. */
-			/* L1 = 3X^2 + aZ^4 */
-			/*                          T1: used for aZ^4. */
-			ec_pow2(l1, point->x, ctx);
-			ec_mulm(l1, l1, mpi_const(MPI_C_THREE), ctx);
-			ec_powm(t1, point->z, mpi_const(MPI_C_FOUR), ctx);
-			ec_mulm(t1, t1, ctx->a, ctx);
-			ec_addm(l1, l1, t1, ctx);
-		}
-		/* Z3 = 2YZ */
-		ec_mulm(z3, point->y, point->z, ctx);
-		ec_mul2(z3, z3, ctx);
-
-		/* L2 = 4XY^2 */
-		/*                              T2: used for Y2; required later. */
-		ec_pow2(t2, point->y, ctx);
-		ec_mulm(l2, t2, point->x, ctx);
-		ec_mulm(l2, l2, mpi_const(MPI_C_FOUR), ctx);
-
-		/* X3 = L1^2 - 2L2 */
-		/*                              T1: used for L2^2. */
-		ec_pow2(x3, l1, ctx);
-		ec_mul2(t1, l2, ctx);
-		ec_subm(x3, x3, t1, ctx);
-
-		/* L3 = 8Y^4 */
-		/*                              T2: taken from above. */
-		ec_pow2(t2, t2, ctx);
-		ec_mulm(l3, t2, mpi_const(MPI_C_EIGHT), ctx);
-
-		/* Y3 = L1(L2 - X3) - L3 */
-		ec_subm(y3, l2, x3, ctx);
-		ec_mulm(y3, y3, l1, ctx);
-		ec_subm(y3, y3, l3, ctx);
-	}
-
-#undef x3
-#undef y3
-#undef z3
-#undef t1
-#undef t2
-#undef t3
-#undef l1
-#undef l2
-#undef l3
-}
-
-/*  RESULT = 2 * POINT  (Montgomery version). */
-static void dup_point_montgomery(MPI_POINT result,
-				MPI_POINT point, struct mpi_ec_ctx *ctx)
-{
-	(void)result;
-	(void)point;
-	(void)ctx;
-	log_fatal("%s: %s not yet supported\n",
-			"mpi_ec_dup_point", "Montgomery");
-}
-
-/*  RESULT = 2 * POINT  (Twisted Edwards version). */
-static void dup_point_edwards(MPI_POINT result,
-		MPI_POINT point, struct mpi_ec_ctx *ctx)
-{
-#define X1 (point->x)
-#define Y1 (point->y)
-#define Z1 (point->z)
-#define X3 (result->x)
-#define Y3 (result->y)
-#define Z3 (result->z)
-#define B (ctx->t.scratch[0])
-#define C (ctx->t.scratch[1])
-#define D (ctx->t.scratch[2])
-#define E (ctx->t.scratch[3])
-#define F (ctx->t.scratch[4])
-#define H (ctx->t.scratch[5])
-#define J (ctx->t.scratch[6])
-
-	/* Compute: (X_3 : Y_3 : Z_3) = 2( X_1 : Y_1 : Z_1 ) */
-
-	/* B = (X_1 + Y_1)^2  */
-	ctx->addm(B, X1, Y1, ctx);
-	ctx->pow2(B, B, ctx);
-
-	/* C = X_1^2 */
-	/* D = Y_1^2 */
-	ctx->pow2(C, X1, ctx);
-	ctx->pow2(D, Y1, ctx);
-
-	/* E = aC */
-	if (ctx->dialect == ECC_DIALECT_ED25519)
-		ctx->subm(E, ctx->p, C, ctx);
-	else
-		ctx->mulm(E, ctx->a, C, ctx);
-
-	/* F = E + D */
-	ctx->addm(F, E, D, ctx);
-
-	/* H = Z_1^2 */
-	ctx->pow2(H, Z1, ctx);
-
-	/* J = F - 2H */
-	ctx->mul2(J, H, ctx);
-	ctx->subm(J, F, J, ctx);
-
-	/* X_3 = (B - C - D) · J */
-	ctx->subm(X3, B, C, ctx);
-	ctx->subm(X3, X3, D, ctx);
-	ctx->mulm(X3, X3, J, ctx);
-
-	/* Y_3 = F · (E - D) */
-	ctx->subm(Y3, E, D, ctx);
-	ctx->mulm(Y3, Y3, F, ctx);
-
-	/* Z_3 = F · J */
-	ctx->mulm(Z3, F, J, ctx);
-
-#undef X1
-#undef Y1
-#undef Z1
-#undef X3
-#undef Y3
-#undef Z3
-#undef B
-#undef C
-#undef D
-#undef E
-#undef F
-#undef H
-#undef J
-}
-
-/*  RESULT = 2 * POINT  */
-static void
-mpi_ec_dup_point(MPI_POINT result, MPI_POINT point, struct mpi_ec_ctx *ctx)
-{
-	switch (ctx->model) {
-	case MPI_EC_WEIERSTRASS:
-		dup_point_weierstrass(result, point, ctx);
-		break;
-	case MPI_EC_MONTGOMERY:
-		dup_point_montgomery(result, point, ctx);
-		break;
-	case MPI_EC_EDWARDS:
-		dup_point_edwards(result, point, ctx);
-		break;
-	}
-}
-
-/* RESULT = P1 + P2  (Weierstrass version).*/
-static void add_points_weierstrass(MPI_POINT result,
-		MPI_POINT p1, MPI_POINT p2,
-		struct mpi_ec_ctx *ctx)
-{
-#define x1 (p1->x)
-#define y1 (p1->y)
-#define z1 (p1->z)
-#define x2 (p2->x)
-#define y2 (p2->y)
-#define z2 (p2->z)
-#define x3 (result->x)
-#define y3 (result->y)
-#define z3 (result->z)
-#define l1 (ctx->t.scratch[0])
-#define l2 (ctx->t.scratch[1])
-#define l3 (ctx->t.scratch[2])
-#define l4 (ctx->t.scratch[3])
-#define l5 (ctx->t.scratch[4])
-#define l6 (ctx->t.scratch[5])
-#define l7 (ctx->t.scratch[6])
-#define l8 (ctx->t.scratch[7])
-#define l9 (ctx->t.scratch[8])
-#define t1 (ctx->t.scratch[9])
-#define t2 (ctx->t.scratch[10])
-
-	if ((!mpi_cmp(x1, x2)) && (!mpi_cmp(y1, y2)) && (!mpi_cmp(z1, z2))) {
-		/* Same point; need to call the duplicate function.  */
-		mpi_ec_dup_point(result, p1, ctx);
-	} else if (!mpi_cmp_ui(z1, 0)) {
-		/* P1 is at infinity.  */
-		mpi_set(x3, p2->x);
-		mpi_set(y3, p2->y);
-		mpi_set(z3, p2->z);
-	} else if (!mpi_cmp_ui(z2, 0)) {
-		/* P2 is at infinity.  */
-		mpi_set(x3, p1->x);
-		mpi_set(y3, p1->y);
-		mpi_set(z3, p1->z);
-	} else {
-		int z1_is_one = !mpi_cmp_ui(z1, 1);
-		int z2_is_one = !mpi_cmp_ui(z2, 1);
-
-		/* l1 = x1 z2^2  */
-		/* l2 = x2 z1^2  */
-		if (z2_is_one)
-			mpi_set(l1, x1);
-		else {
-			ec_pow2(l1, z2, ctx);
-			ec_mulm(l1, l1, x1, ctx);
-		}
-		if (z1_is_one)
-			mpi_set(l2, x2);
-		else {
-			ec_pow2(l2, z1, ctx);
-			ec_mulm(l2, l2, x2, ctx);
-		}
-		/* l3 = l1 - l2 */
-		ec_subm(l3, l1, l2, ctx);
-		/* l4 = y1 z2^3  */
-		ec_powm(l4, z2, mpi_const(MPI_C_THREE), ctx);
-		ec_mulm(l4, l4, y1, ctx);
-		/* l5 = y2 z1^3  */
-		ec_powm(l5, z1, mpi_const(MPI_C_THREE), ctx);
-		ec_mulm(l5, l5, y2, ctx);
-		/* l6 = l4 - l5  */
-		ec_subm(l6, l4, l5, ctx);
-
-		if (!mpi_cmp_ui(l3, 0)) {
-			if (!mpi_cmp_ui(l6, 0)) {
-				/* P1 and P2 are the same - use duplicate function. */
-				mpi_ec_dup_point(result, p1, ctx);
-			} else {
-				/* P1 is the inverse of P2.  */
-				mpi_set_ui(x3, 1);
-				mpi_set_ui(y3, 1);
-				mpi_set_ui(z3, 0);
-			}
-		} else {
-			/* l7 = l1 + l2  */
-			ec_addm(l7, l1, l2, ctx);
-			/* l8 = l4 + l5  */
-			ec_addm(l8, l4, l5, ctx);
-			/* z3 = z1 z2 l3  */
-			ec_mulm(z3, z1, z2, ctx);
-			ec_mulm(z3, z3, l3, ctx);
-			/* x3 = l6^2 - l7 l3^2  */
-			ec_pow2(t1, l6, ctx);
-			ec_pow2(t2, l3, ctx);
-			ec_mulm(t2, t2, l7, ctx);
-			ec_subm(x3, t1, t2, ctx);
-			/* l9 = l7 l3^2 - 2 x3  */
-			ec_mul2(t1, x3, ctx);
-			ec_subm(l9, t2, t1, ctx);
-			/* y3 = (l9 l6 - l8 l3^3)/2  */
-			ec_mulm(l9, l9, l6, ctx);
-			ec_powm(t1, l3, mpi_const(MPI_C_THREE), ctx); /* fixme: Use saved value*/
-			ec_mulm(t1, t1, l8, ctx);
-			ec_subm(y3, l9, t1, ctx);
-			ec_mulm(y3, y3, ec_get_two_inv_p(ctx), ctx);
-		}
-	}
-
-#undef x1
-#undef y1
-#undef z1
-#undef x2
-#undef y2
-#undef z2
-#undef x3
-#undef y3
-#undef z3
-#undef l1
-#undef l2
-#undef l3
-#undef l4
-#undef l5
-#undef l6
-#undef l7
-#undef l8
-#undef l9
-#undef t1
-#undef t2
-}
-
-/* RESULT = P1 + P2  (Montgomery version).*/
-static void add_points_montgomery(MPI_POINT result,
-		MPI_POINT p1, MPI_POINT p2,
-		struct mpi_ec_ctx *ctx)
-{
-	(void)result;
-	(void)p1;
-	(void)p2;
-	(void)ctx;
-	log_fatal("%s: %s not yet supported\n",
-			"mpi_ec_add_points", "Montgomery");
-}
-
-/* RESULT = P1 + P2  (Twisted Edwards version).*/
-static void add_points_edwards(MPI_POINT result,
-		MPI_POINT p1, MPI_POINT p2,
-		struct mpi_ec_ctx *ctx)
-{
-#define X1 (p1->x)
-#define Y1 (p1->y)
-#define Z1 (p1->z)
-#define X2 (p2->x)
-#define Y2 (p2->y)
-#define Z2 (p2->z)
-#define X3 (result->x)
-#define Y3 (result->y)
-#define Z3 (result->z)
-#define A (ctx->t.scratch[0])
-#define B (ctx->t.scratch[1])
-#define C (ctx->t.scratch[2])
-#define D (ctx->t.scratch[3])
-#define E (ctx->t.scratch[4])
-#define F (ctx->t.scratch[5])
-#define G (ctx->t.scratch[6])
-#define tmp (ctx->t.scratch[7])
-
-	point_resize(result, ctx);
-
-	/* Compute: (X_3 : Y_3 : Z_3) = (X_1 : Y_1 : Z_1) + (X_2 : Y_2 : Z_3) */
-
-	/* A = Z1 · Z2 */
-	ctx->mulm(A, Z1, Z2, ctx);
-
-	/* B = A^2 */
-	ctx->pow2(B, A, ctx);
-
-	/* C = X1 · X2 */
-	ctx->mulm(C, X1, X2, ctx);
-
-	/* D = Y1 · Y2 */
-	ctx->mulm(D, Y1, Y2, ctx);
-
-	/* E = d · C · D */
-	ctx->mulm(E, ctx->b, C, ctx);
-	ctx->mulm(E, E, D, ctx);
-
-	/* F = B - E */
-	ctx->subm(F, B, E, ctx);
-
-	/* G = B + E */
-	ctx->addm(G, B, E, ctx);
-
-	/* X_3 = A · F · ((X_1 + Y_1) · (X_2 + Y_2) - C - D) */
-	ctx->addm(tmp, X1, Y1, ctx);
-	ctx->addm(X3, X2, Y2, ctx);
-	ctx->mulm(X3, X3, tmp, ctx);
-	ctx->subm(X3, X3, C, ctx);
-	ctx->subm(X3, X3, D, ctx);
-	ctx->mulm(X3, X3, F, ctx);
-	ctx->mulm(X3, X3, A, ctx);
-
-	/* Y_3 = A · G · (D - aC) */
-	if (ctx->dialect == ECC_DIALECT_ED25519) {
-		ctx->addm(Y3, D, C, ctx);
-	} else {
-		ctx->mulm(Y3, ctx->a, C, ctx);
-		ctx->subm(Y3, D, Y3, ctx);
-	}
-	ctx->mulm(Y3, Y3, G, ctx);
-	ctx->mulm(Y3, Y3, A, ctx);
-
-	/* Z_3 = F · G */
-	ctx->mulm(Z3, F, G, ctx);
-
-
-#undef X1
-#undef Y1
-#undef Z1
-#undef X2
-#undef Y2
-#undef Z2
-#undef X3
-#undef Y3
-#undef Z3
-#undef A
-#undef B
-#undef C
-#undef D
-#undef E
-#undef F
-#undef G
-#undef tmp
-}
-
-/* Compute a step of Montgomery Ladder (only use X and Z in the point).
- * Inputs:  P1, P2, and x-coordinate of DIF = P1 - P1.
- * Outputs: PRD = 2 * P1 and  SUM = P1 + P2.
- */
-static void montgomery_ladder(MPI_POINT prd, MPI_POINT sum,
-		MPI_POINT p1, MPI_POINT p2, MPI dif_x,
-		struct mpi_ec_ctx *ctx)
-{
-	ctx->addm(sum->x, p2->x, p2->z, ctx);
-	ctx->subm(p2->z, p2->x, p2->z, ctx);
-	ctx->addm(prd->x, p1->x, p1->z, ctx);
-	ctx->subm(p1->z, p1->x, p1->z, ctx);
-	ctx->mulm(p2->x, p1->z, sum->x, ctx);
-	ctx->mulm(p2->z, prd->x, p2->z, ctx);
-	ctx->pow2(p1->x, prd->x, ctx);
-	ctx->pow2(p1->z, p1->z, ctx);
-	ctx->addm(sum->x, p2->x, p2->z, ctx);
-	ctx->subm(p2->z, p2->x, p2->z, ctx);
-	ctx->mulm(prd->x, p1->x, p1->z, ctx);
-	ctx->subm(p1->z, p1->x, p1->z, ctx);
-	ctx->pow2(sum->x, sum->x, ctx);
-	ctx->pow2(sum->z, p2->z, ctx);
-	ctx->mulm(prd->z, p1->z, ctx->a, ctx); /* CTX->A: (a-2)/4 */
-	ctx->mulm(sum->z, sum->z, dif_x, ctx);
-	ctx->addm(prd->z, p1->x, prd->z, ctx);
-	ctx->mulm(prd->z, prd->z, p1->z, ctx);
-}
-
-/* RESULT = P1 + P2 */
-void mpi_ec_add_points(MPI_POINT result,
-		MPI_POINT p1, MPI_POINT p2,
-		struct mpi_ec_ctx *ctx)
-{
-	switch (ctx->model) {
-	case MPI_EC_WEIERSTRASS:
-		add_points_weierstrass(result, p1, p2, ctx);
-		break;
-	case MPI_EC_MONTGOMERY:
-		add_points_montgomery(result, p1, p2, ctx);
-		break;
-	case MPI_EC_EDWARDS:
-		add_points_edwards(result, p1, p2, ctx);
-		break;
-	}
-}
-EXPORT_SYMBOL_GPL(mpi_ec_add_points);
-
-/* Scalar point multiplication - the main function for ECC.  If takes
- * an integer SCALAR and a POINT as well as the usual context CTX.
- * RESULT will be set to the resulting point.
- */
-void mpi_ec_mul_point(MPI_POINT result,
-			MPI scalar, MPI_POINT point,
-			struct mpi_ec_ctx *ctx)
-{
-	MPI x1, y1, z1, k, h, yy;
-	unsigned int i, loops;
-	struct gcry_mpi_point p1, p2, p1inv;
-
-	if (ctx->model == MPI_EC_EDWARDS) {
-		/* Simple left to right binary method.  Algorithm 3.27 from
-		 * {author={Hankerson, Darrel and Menezes, Alfred J. and Vanstone, Scott},
-		 *  title = {Guide to Elliptic Curve Cryptography},
-		 *  year = {2003}, isbn = {038795273X},
-		 *  url = {http://www.cacr.math.uwaterloo.ca/ecc/},
-		 *  publisher = {Springer-Verlag New York, Inc.}}
-		 */
-		unsigned int nbits;
-		int j;
-
-		if (mpi_cmp(scalar, ctx->p) >= 0)
-			nbits = mpi_get_nbits(scalar);
-		else
-			nbits = mpi_get_nbits(ctx->p);
-
-		mpi_set_ui(result->x, 0);
-		mpi_set_ui(result->y, 1);
-		mpi_set_ui(result->z, 1);
-		point_resize(point, ctx);
-
-		point_resize(result, ctx);
-		point_resize(point, ctx);
-
-		for (j = nbits-1; j >= 0; j--) {
-			mpi_ec_dup_point(result, result, ctx);
-			if (mpi_test_bit(scalar, j))
-				mpi_ec_add_points(result, result, point, ctx);
-		}
-		return;
-	} else if (ctx->model == MPI_EC_MONTGOMERY) {
-		unsigned int nbits;
-		int j;
-		struct gcry_mpi_point p1_, p2_;
-		MPI_POINT q1, q2, prd, sum;
-		unsigned long sw;
-		mpi_size_t rsize;
-
-		/* Compute scalar point multiplication with Montgomery Ladder.
-		 * Note that we don't use Y-coordinate in the points at all.
-		 * RESULT->Y will be filled by zero.
-		 */
-
-		nbits = mpi_get_nbits(scalar);
-		point_init(&p1);
-		point_init(&p2);
-		point_init(&p1_);
-		point_init(&p2_);
-		mpi_set_ui(p1.x, 1);
-		mpi_free(p2.x);
-		p2.x = mpi_copy(point->x);
-		mpi_set_ui(p2.z, 1);
-
-		point_resize(&p1, ctx);
-		point_resize(&p2, ctx);
-		point_resize(&p1_, ctx);
-		point_resize(&p2_, ctx);
-
-		mpi_resize(point->x, ctx->p->nlimbs);
-		point->x->nlimbs = ctx->p->nlimbs;
-
-		q1 = &p1;
-		q2 = &p2;
-		prd = &p1_;
-		sum = &p2_;
-
-		for (j = nbits-1; j >= 0; j--) {
-			sw = mpi_test_bit(scalar, j);
-			point_swap_cond(q1, q2, sw, ctx);
-			montgomery_ladder(prd, sum, q1, q2, point->x, ctx);
-			point_swap_cond(prd, sum, sw, ctx);
-			swap(q1, prd);
-			swap(q2, sum);
-		}
-
-		mpi_clear(result->y);
-		sw = (nbits & 1);
-		point_swap_cond(&p1, &p1_, sw, ctx);
-
-		rsize = p1.z->nlimbs;
-		MPN_NORMALIZE(p1.z->d, rsize);
-		if (rsize == 0) {
-			mpi_set_ui(result->x, 1);
-			mpi_set_ui(result->z, 0);
-		} else {
-			z1 = mpi_new(0);
-			ec_invm(z1, p1.z, ctx);
-			ec_mulm(result->x, p1.x, z1, ctx);
-			mpi_set_ui(result->z, 1);
-			mpi_free(z1);
-		}
-
-		point_free(&p1);
-		point_free(&p2);
-		point_free(&p1_);
-		point_free(&p2_);
-		return;
-	}
-
-	x1 = mpi_alloc_like(ctx->p);
-	y1 = mpi_alloc_like(ctx->p);
-	h  = mpi_alloc_like(ctx->p);
-	k  = mpi_copy(scalar);
-	yy = mpi_copy(point->y);
-
-	if (mpi_has_sign(k)) {
-		k->sign = 0;
-		ec_invm(yy, yy, ctx);
-	}
-
-	if (!mpi_cmp_ui(point->z, 1)) {
-		mpi_set(x1, point->x);
-		mpi_set(y1, yy);
-	} else {
-		MPI z2, z3;
-
-		z2 = mpi_alloc_like(ctx->p);
-		z3 = mpi_alloc_like(ctx->p);
-		ec_mulm(z2, point->z, point->z, ctx);
-		ec_mulm(z3, point->z, z2, ctx);
-		ec_invm(z2, z2, ctx);
-		ec_mulm(x1, point->x, z2, ctx);
-		ec_invm(z3, z3, ctx);
-		ec_mulm(y1, yy, z3, ctx);
-		mpi_free(z2);
-		mpi_free(z3);
-	}
-	z1 = mpi_copy(mpi_const(MPI_C_ONE));
-
-	mpi_mul(h, k, mpi_const(MPI_C_THREE)); /* h = 3k */
-	loops = mpi_get_nbits(h);
-	if (loops < 2) {
-		/* If SCALAR is zero, the above mpi_mul sets H to zero and thus
-		 * LOOPs will be zero.  To avoid an underflow of I in the main
-		 * loop we set LOOP to 2 and the result to (0,0,0).
-		 */
-		loops = 2;
-		mpi_clear(result->x);
-		mpi_clear(result->y);
-		mpi_clear(result->z);
-	} else {
-		mpi_set(result->x, point->x);
-		mpi_set(result->y, yy);
-		mpi_set(result->z, point->z);
-	}
-	mpi_free(yy); yy = NULL;
-
-	p1.x = x1; x1 = NULL;
-	p1.y = y1; y1 = NULL;
-	p1.z = z1; z1 = NULL;
-	point_init(&p2);
-	point_init(&p1inv);
-
-	/* Invert point: y = p - y mod p  */
-	point_set(&p1inv, &p1);
-	ec_subm(p1inv.y, ctx->p, p1inv.y, ctx);
-
-	for (i = loops-2; i > 0; i--) {
-		mpi_ec_dup_point(result, result, ctx);
-		if (mpi_test_bit(h, i) == 1 && mpi_test_bit(k, i) == 0) {
-			point_set(&p2, result);
-			mpi_ec_add_points(result, &p2, &p1, ctx);
-		}
-		if (mpi_test_bit(h, i) == 0 && mpi_test_bit(k, i) == 1) {
-			point_set(&p2, result);
-			mpi_ec_add_points(result, &p2, &p1inv, ctx);
-		}
-	}
-
-	point_free(&p1);
-	point_free(&p2);
-	point_free(&p1inv);
-	mpi_free(h);
-	mpi_free(k);
-}
-EXPORT_SYMBOL_GPL(mpi_ec_mul_point);
-
-/* Return true if POINT is on the curve described by CTX.  */
-int mpi_ec_curve_point(MPI_POINT point, struct mpi_ec_ctx *ctx)
-{
-	int res = 0;
-	MPI x, y, w;
-
-	x = mpi_new(0);
-	y = mpi_new(0);
-	w = mpi_new(0);
-
-	/* Check that the point is in range.  This needs to be done here and
-	 * not after conversion to affine coordinates.
-	 */
-	if (mpi_cmpabs(point->x, ctx->p) >= 0)
-		goto leave;
-	if (mpi_cmpabs(point->y, ctx->p) >= 0)
-		goto leave;
-	if (mpi_cmpabs(point->z, ctx->p) >= 0)
-		goto leave;
-
-	switch (ctx->model) {
-	case MPI_EC_WEIERSTRASS:
-		{
-			MPI xxx;
-
-			if (mpi_ec_get_affine(x, y, point, ctx))
-				goto leave;
-
-			xxx = mpi_new(0);
-
-			/* y^2 == x^3 + a·x + b */
-			ec_pow2(y, y, ctx);
-
-			ec_pow3(xxx, x, ctx);
-			ec_mulm(w, ctx->a, x, ctx);
-			ec_addm(w, w, ctx->b, ctx);
-			ec_addm(w, w, xxx, ctx);
-
-			if (!mpi_cmp(y, w))
-				res = 1;
-
-			mpi_free(xxx);
-		}
-		break;
-
-	case MPI_EC_MONTGOMERY:
-		{
-#define xx y
-			/* With Montgomery curve, only X-coordinate is valid. */
-			if (mpi_ec_get_affine(x, NULL, point, ctx))
-				goto leave;
-
-			/* The equation is: b * y^2 == x^3 + a · x^2 + x */
-			/* We check if right hand is quadratic residue or not by
-			 * Euler's criterion.
-			 */
-			/* CTX->A has (a-2)/4 and CTX->B has b^-1 */
-			ec_mulm(w, ctx->a, mpi_const(MPI_C_FOUR), ctx);
-			ec_addm(w, w, mpi_const(MPI_C_TWO), ctx);
-			ec_mulm(w, w, x, ctx);
-			ec_pow2(xx, x, ctx);
-			ec_addm(w, w, xx, ctx);
-			ec_addm(w, w, mpi_const(MPI_C_ONE), ctx);
-			ec_mulm(w, w, x, ctx);
-			ec_mulm(w, w, ctx->b, ctx);
-#undef xx
-			/* Compute Euler's criterion: w^(p-1)/2 */
-#define p_minus1 y
-			ec_subm(p_minus1, ctx->p, mpi_const(MPI_C_ONE), ctx);
-			mpi_rshift(p_minus1, p_minus1, 1);
-			ec_powm(w, w, p_minus1, ctx);
-
-			res = !mpi_cmp_ui(w, 1);
-#undef p_minus1
-		}
-		break;
-
-	case MPI_EC_EDWARDS:
-		{
-			if (mpi_ec_get_affine(x, y, point, ctx))
-				goto leave;
-
-			mpi_resize(w, ctx->p->nlimbs);
-			w->nlimbs = ctx->p->nlimbs;
-
-			/* a · x^2 + y^2 - 1 - b · x^2 · y^2 == 0 */
-			ctx->pow2(x, x, ctx);
-			ctx->pow2(y, y, ctx);
-			if (ctx->dialect == ECC_DIALECT_ED25519)
-				ctx->subm(w, ctx->p, x, ctx);
-			else
-				ctx->mulm(w, ctx->a, x, ctx);
-			ctx->addm(w, w, y, ctx);
-			ctx->mulm(x, x, y, ctx);
-			ctx->mulm(x, x, ctx->b, ctx);
-			ctx->subm(w, w, x, ctx);
-			if (!mpi_cmp_ui(w, 1))
-				res = 1;
-		}
-		break;
-	}
-
-leave:
-	mpi_free(w);
-	mpi_free(x);
-	mpi_free(y);
-
-	return res;
-}
-EXPORT_SYMBOL_GPL(mpi_ec_curve_point);
-- 
2.39.2

-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt




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