/*
- * Copyright 2001-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2001-2019 The OpenSSL Project Authors. All Rights Reserved.
* Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved
*
* Licensed under the OpenSSL license (the "License"). You may not use
#include <openssl/err.h>
#include <openssl/symhacks.h>
-#include "ec_lcl.h"
+#include "ec_local.h"
const EC_METHOD *EC_GFp_simple_method(void)
{
ec_GFp_simple_field_mul,
ec_GFp_simple_field_sqr,
0 /* field_div */ ,
+ ec_GFp_simple_field_inv,
0 /* field_encode */ ,
0 /* field_decode */ ,
0, /* field_set_to_one */
ret = 1;
err:
- if (ctx != NULL)
- BN_CTX_end(ctx);
+ BN_CTX_end(ctx);
BN_CTX_free(new_ctx);
return ret;
}
}
}
} else {
- if (!BN_mod_inverse(Z_1, Z_, group->field, ctx)) {
+ if (!group->meth->field_inv(group, Z_1, Z_, ctx)) {
ECerr(EC_F_EC_GFP_SIMPLE_POINT_GET_AFFINE_COORDINATES,
ERR_R_BN_LIB);
goto err;
ret = 1;
end:
- if (ctx) /* otherwise we already called BN_CTX_end */
- BN_CTX_end(ctx);
+ BN_CTX_end(ctx);
BN_CTX_free(new_ctx);
return ret;
}
* points[i]->Z by its inverse.
*/
- if (!BN_mod_inverse(tmp, prod_Z[num - 1], group->field, ctx)) {
+ if (!group->meth->field_inv(group, tmp, prod_Z[num - 1], ctx)) {
ECerr(EC_F_EC_GFP_SIMPLE_POINTS_MAKE_AFFINE, ERR_R_BN_LIB);
goto err;
}
return BN_mod_sqr(r, a, group->field, ctx);
}
+/*-
+ * Computes the multiplicative inverse of a in GF(p), storing the result in r.
+ * If a is zero (or equivalent), you'll get a EC_R_CANNOT_INVERT error.
+ * Since we don't have a Mont structure here, SCA hardening is with blinding.
+ */
+int ec_GFp_simple_field_inv(const EC_GROUP *group, BIGNUM *r, const BIGNUM *a,
+ BN_CTX *ctx)
+{
+ BIGNUM *e = NULL;
+ BN_CTX *new_ctx = NULL;
+ int ret = 0;
+
+ if (ctx == NULL && (ctx = new_ctx = BN_CTX_secure_new()) == NULL)
+ return 0;
+
+ BN_CTX_start(ctx);
+ if ((e = BN_CTX_get(ctx)) == NULL)
+ goto err;
+
+ do {
+ if (!BN_priv_rand_range(e, group->field))
+ goto err;
+ } while (BN_is_zero(e));
+
+ /* r := a * e */
+ if (!group->meth->field_mul(group, r, a, e, ctx))
+ goto err;
+ /* r := 1/(a * e) */
+ if (!BN_mod_inverse(r, r, group->field, ctx)) {
+ ECerr(EC_F_EC_GFP_SIMPLE_FIELD_INV, EC_R_CANNOT_INVERT);
+ goto err;
+ }
+ /* r := e/(a * e) = 1/a */
+ if (!group->meth->field_mul(group, r, r, e, ctx))
+ goto err;
+
+ ret = 1;
+
+ err:
+ BN_CTX_end(ctx);
+ BN_CTX_free(new_ctx);
+ return ret;
+}
+
/*-
* Apply randomization of EC point projective coordinates:
*
}
/*-
- * Differential addition-and-doubling using Eq. (8) and (10) from Izu-Takagi
+ * Differential addition-and-doubling using Eq. (9) and (10) from Izu-Takagi
* "A fast parallel elliptic curve multiplication resistant against side channel
* attacks", as described at
- * https://hyperelliptic.org/EFD/g1p/auto-shortw-xz.html#ladder-ladd-2002-it-3
+ * https://hyperelliptic.org/EFD/g1p/auto-shortw-xz.html#ladder-ladd-2002-it-4
*/
int ec_GFp_simple_ladder_step(const EC_GROUP *group,
EC_POINT *r, EC_POINT *s,
|| !group->meth->field_mul(group, t2, r->X, s->Z, ctx)
|| !group->meth->field_mul(group, t3, r->Z, s->X, ctx)
|| !group->meth->field_mul(group, t4, group->a, t1, ctx)
- || !BN_mod_sub_quick(t4, t0, t4, group->field)
- || !BN_mod_add_quick(t5, t3, t2, group->field)
- || !group->meth->field_sqr(group, t4, t4, ctx)
- || !group->meth->field_mul(group, t5, t1, t5, ctx)
- || !BN_mod_lshift_quick(t0, group->b, 2, group->field)
- || !group->meth->field_mul(group, t5, t0, t5, ctx)
- || !BN_mod_sub_quick(t5, t4, t5, group->field)
+ || !BN_mod_add_quick(t0, t0, t4, group->field)
+ || !BN_mod_add_quick(t4, t3, t2, group->field)
+ || !group->meth->field_mul(group, t0, t4, t0, ctx)
+ || !group->meth->field_sqr(group, t1, t1, ctx)
+ || !BN_mod_lshift_quick(t7, group->b, 2, group->field)
+ || !group->meth->field_mul(group, t1, t7, t1, ctx)
+ || !BN_mod_lshift1_quick(t0, t0, group->field)
+ || !BN_mod_add_quick(t0, t1, t0, group->field)
+ || !BN_mod_sub_quick(t1, t2, t3, group->field)
+ || !group->meth->field_sqr(group, t1, t1, ctx)
+ || !group->meth->field_mul(group, t3, t1, p->X, ctx)
+ || !group->meth->field_mul(group, t0, p->Z, t0, ctx)
/* s->X coord output */
- || !group->meth->field_mul(group, s->X, t5, p->Z, ctx)
- || !BN_mod_sub_quick(t3, t2, t3, group->field)
- || !group->meth->field_sqr(group, t3, t3, ctx)
+ || !BN_mod_sub_quick(s->X, t0, t3, group->field)
/* s->Z coord output */
- || !group->meth->field_mul(group, s->Z, t3, p->X, ctx)
- || !group->meth->field_sqr(group, t2, r->X, ctx)
- || !group->meth->field_sqr(group, t4, r->Z, ctx)
- || !group->meth->field_mul(group, t1, t4, group->a, ctx)
- || !BN_mod_add_quick(t6, r->X, r->Z, group->field)
+ || !group->meth->field_mul(group, s->Z, p->Z, t1, ctx)
+ || !group->meth->field_sqr(group, t3, r->X, ctx)
+ || !group->meth->field_sqr(group, t2, r->Z, ctx)
+ || !group->meth->field_mul(group, t4, t2, group->a, ctx)
+ || !BN_mod_add_quick(t5, r->X, r->Z, group->field)
+ || !group->meth->field_sqr(group, t5, t5, ctx)
+ || !BN_mod_sub_quick(t5, t5, t3, group->field)
+ || !BN_mod_sub_quick(t5, t5, t2, group->field)
+ || !BN_mod_sub_quick(t6, t3, t4, group->field)
|| !group->meth->field_sqr(group, t6, t6, ctx)
- || !BN_mod_sub_quick(t6, t6, t2, group->field)
- || !BN_mod_sub_quick(t6, t6, t4, group->field)
- || !BN_mod_sub_quick(t7, t2, t1, group->field)
- || !group->meth->field_sqr(group, t7, t7, ctx)
- || !group->meth->field_mul(group, t5, t4, t6, ctx)
- || !group->meth->field_mul(group, t5, t0, t5, ctx)
+ || !group->meth->field_mul(group, t0, t2, t5, ctx)
+ || !group->meth->field_mul(group, t0, t7, t0, ctx)
/* r->X coord output */
- || !BN_mod_sub_quick(r->X, t7, t5, group->field)
- || !BN_mod_add_quick(t2, t2, t1, group->field)
- || !group->meth->field_sqr(group, t5, t4, ctx)
- || !group->meth->field_mul(group, t5, t5, t0, ctx)
- || !group->meth->field_mul(group, t6, t6, t2, ctx)
- || !BN_mod_lshift1_quick(t6, t6, group->field)
+ || !BN_mod_sub_quick(r->X, t6, t0, group->field)
+ || !BN_mod_add_quick(t6, t3, t4, group->field)
+ || !group->meth->field_sqr(group, t3, t2, ctx)
+ || !group->meth->field_mul(group, t7, t3, t7, ctx)
+ || !group->meth->field_mul(group, t5, t5, t6, ctx)
+ || !BN_mod_lshift1_quick(t5, t5, group->field)
/* r->Z coord output */
- || !BN_mod_add_quick(r->Z, t5, t6, group->field))
+ || !BN_mod_add_quick(r->Z, t7, t5, group->field))
goto err;
ret = 1;