openssl/crypto/ec/ec_lcl.h

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/*
* Copyright 2001-2018 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
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <stdlib.h>
#include <openssl/obj_mac.h>
#include <openssl/ec.h>
#include <openssl/bn.h>
#include "internal/refcount.h"
#include "internal/ec_int.h"
#include "curve448/curve448_lcl.h"
#if defined(__SUNPRO_C)
# if __SUNPRO_C >= 0x520
# pragma error_messages (off,E_ARRAY_OF_INCOMPLETE_NONAME,E_ARRAY_OF_INCOMPLETE)
# endif
#endif
/* Use default functions for poin2oct, oct2point and compressed coordinates */
#define EC_FLAGS_DEFAULT_OCT 0x1
/* Use custom formats for EC_GROUP, EC_POINT and EC_KEY */
#define EC_FLAGS_CUSTOM_CURVE 0x2
/* Curve does not support signing operations */
#define EC_FLAGS_NO_SIGN 0x4
/*
* Structure details are not part of the exported interface, so all this may
* change in future versions.
*/
struct ec_method_st {
/* Various method flags */
int flags;
/* used by EC_METHOD_get_field_type: */
int field_type; /* a NID */
/*
* used by EC_GROUP_new, EC_GROUP_free, EC_GROUP_clear_free,
* EC_GROUP_copy:
*/
int (*group_init) (EC_GROUP *);
void (*group_finish) (EC_GROUP *);
void (*group_clear_finish) (EC_GROUP *);
int (*group_copy) (EC_GROUP *, const EC_GROUP *);
/* used by EC_GROUP_set_curve_GFp, EC_GROUP_get_curve_GFp, */
/* EC_GROUP_set_curve_GF2m, and EC_GROUP_get_curve_GF2m: */
int (*group_set_curve) (EC_GROUP *, const BIGNUM *p, const BIGNUM *a,
const BIGNUM *b, BN_CTX *);
int (*group_get_curve) (const EC_GROUP *, BIGNUM *p, BIGNUM *a, BIGNUM *b,
BN_CTX *);
/* used by EC_GROUP_get_degree: */
int (*group_get_degree) (const EC_GROUP *);
int (*group_order_bits) (const EC_GROUP *);
/* used by EC_GROUP_check: */
int (*group_check_discriminant) (const EC_GROUP *, BN_CTX *);
/*
* used by EC_POINT_new, EC_POINT_free, EC_POINT_clear_free,
* EC_POINT_copy:
*/
int (*point_init) (EC_POINT *);
void (*point_finish) (EC_POINT *);
void (*point_clear_finish) (EC_POINT *);
int (*point_copy) (EC_POINT *, const EC_POINT *);
/*-
* used by EC_POINT_set_to_infinity,
* EC_POINT_set_Jprojective_coordinates_GFp,
* EC_POINT_get_Jprojective_coordinates_GFp,
* EC_POINT_set_affine_coordinates_GFp, ..._GF2m,
* EC_POINT_get_affine_coordinates_GFp, ..._GF2m,
* EC_POINT_set_compressed_coordinates_GFp, ..._GF2m:
*/
int (*point_set_to_infinity) (const EC_GROUP *, EC_POINT *);
int (*point_set_Jprojective_coordinates_GFp) (const EC_GROUP *,
EC_POINT *, const BIGNUM *x,
const BIGNUM *y,
const BIGNUM *z, BN_CTX *);
int (*point_get_Jprojective_coordinates_GFp) (const EC_GROUP *,
const EC_POINT *, BIGNUM *x,
BIGNUM *y, BIGNUM *z,
BN_CTX *);
int (*point_set_affine_coordinates) (const EC_GROUP *, EC_POINT *,
const BIGNUM *x, const BIGNUM *y,
BN_CTX *);
int (*point_get_affine_coordinates) (const EC_GROUP *, const EC_POINT *,
BIGNUM *x, BIGNUM *y, BN_CTX *);
int (*point_set_compressed_coordinates) (const EC_GROUP *, EC_POINT *,
const BIGNUM *x, int y_bit,
BN_CTX *);
/* used by EC_POINT_point2oct, EC_POINT_oct2point: */
size_t (*point2oct) (const EC_GROUP *, const EC_POINT *,
point_conversion_form_t form, unsigned char *buf,
size_t len, BN_CTX *);
int (*oct2point) (const EC_GROUP *, EC_POINT *, const unsigned char *buf,
size_t len, BN_CTX *);
/* used by EC_POINT_add, EC_POINT_dbl, ECP_POINT_invert: */
int (*add) (const EC_GROUP *, EC_POINT *r, const EC_POINT *a,
const EC_POINT *b, BN_CTX *);
int (*dbl) (const EC_GROUP *, EC_POINT *r, const EC_POINT *a, BN_CTX *);
int (*invert) (const EC_GROUP *, EC_POINT *, BN_CTX *);
/*
* used by EC_POINT_is_at_infinity, EC_POINT_is_on_curve, EC_POINT_cmp:
*/
int (*is_at_infinity) (const EC_GROUP *, const EC_POINT *);
int (*is_on_curve) (const EC_GROUP *, const EC_POINT *, BN_CTX *);
int (*point_cmp) (const EC_GROUP *, const EC_POINT *a, const EC_POINT *b,
BN_CTX *);
/* used by EC_POINT_make_affine, EC_POINTs_make_affine: */
int (*make_affine) (const EC_GROUP *, EC_POINT *, BN_CTX *);
int (*points_make_affine) (const EC_GROUP *, size_t num, EC_POINT *[],
BN_CTX *);
/*
* used by EC_POINTs_mul, EC_POINT_mul, EC_POINT_precompute_mult,
* EC_POINT_have_precompute_mult (default implementations are used if the
* 'mul' pointer is 0):
*/
/*-
* mul() calculates the value
*
* r := generator * scalar
* + points[0] * scalars[0]
* + ...
* + points[num-1] * scalars[num-1].
*
* For a fixed point multiplication (scalar != NULL, num == 0)
* or a variable point multiplication (scalar == NULL, num == 1),
* mul() must use a constant time algorithm: in both cases callers
* should provide an input scalar (either scalar or scalars[0])
* in the range [0, ec_group_order); for robustness, implementers
* should handle the case when the scalar has not been reduced, but
* may treat it as an unusual input, without any constant-timeness
* guarantee.
*/
int (*mul) (const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
size_t num, const EC_POINT *points[], const BIGNUM *scalars[],
BN_CTX *);
int (*precompute_mult) (EC_GROUP *group, BN_CTX *);
int (*have_precompute_mult) (const EC_GROUP *group);
/* internal functions */
/*
* 'field_mul', 'field_sqr', and 'field_div' can be used by 'add' and
* 'dbl' so that the same implementations of point operations can be used
* with different optimized implementations of expensive field
* operations:
*/
int (*field_mul) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
const BIGNUM *b, BN_CTX *);
int (*field_sqr) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a, BN_CTX *);
int (*field_div) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
const BIGNUM *b, BN_CTX *);
/* e.g. to Montgomery */
int (*field_encode) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
BN_CTX *);
/* e.g. from Montgomery */
int (*field_decode) (const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
BN_CTX *);
int (*field_set_to_one) (const EC_GROUP *, BIGNUM *r, BN_CTX *);
/* private key operations */
size_t (*priv2oct)(const EC_KEY *eckey, unsigned char *buf, size_t len);
int (*oct2priv)(EC_KEY *eckey, const unsigned char *buf, size_t len);
int (*set_private)(EC_KEY *eckey, const BIGNUM *priv_key);
int (*keygen)(EC_KEY *eckey);
int (*keycheck)(const EC_KEY *eckey);
int (*keygenpub)(EC_KEY *eckey);
int (*keycopy)(EC_KEY *dst, const EC_KEY *src);
void (*keyfinish)(EC_KEY *eckey);
/* custom ECDH operation */
int (*ecdh_compute_key)(unsigned char **pout, size_t *poutlen,
const EC_POINT *pub_key, const EC_KEY *ecdh);
/* Inverse modulo order */
int (*field_inverse_mod_ord)(const EC_GROUP *, BIGNUM *r,
const BIGNUM *x, BN_CTX *);
int (*blind_coordinates)(const EC_GROUP *group, EC_POINT *p, BN_CTX *ctx);
EC point multiplication: add `ladder` scaffold for specialized Montgomery ladder implementations PR #6009 and #6070 replaced the default EC point multiplication path for prime and binary curves with a unified Montgomery ladder implementation with various timing attack defenses (for the common paths when a secret scalar is feed to the point multiplication). The newly introduced default implementation directly used EC_POINT_add/dbl in the main loop. The scaffolding introduced by this commit allows EC_METHODs to define a specialized `ladder_step` function to improve performances by taking advantage of efficient formulas for differential addition-and-doubling and different coordinate systems. - `ladder_pre` is executed before the main loop of the ladder: by default it copies the input point P into S, and doubles it into R. Specialized implementations could, e.g., use this hook to transition to different coordinate systems before copying and doubling; - `ladder_step` is the core of the Montgomery ladder loop: by default it computes `S := R+S; R := 2R;`, but specific implementations could, e.g., implement a more efficient formula for differential addition-and-doubling; - `ladder_post` is executed after the Montgomery ladder loop: by default it's a noop, but specialized implementations could, e.g., use this hook to transition back from the coordinate system used for optimizing the differential addition-and-doubling or recover the y coordinate of the result point. This commit also renames `ec_mul_consttime` to `ec_scalar_mul_ladder`, as it better corresponds to what this function does: nothing can be truly said about the constant-timeness of the overall execution of this function, given that the underlying operations are not necessarily constant-time themselves. What this implementation ensures is that the same fixed sequence of operations is executed for each scalar multiplication (for a given EC_GROUP), with no dependency on the value of the input scalar. Co-authored-by: Sohaib ul Hassan <soh.19.hassan@gmail.com> Co-authored-by: Billy Brumley <bbrumley@gmail.com> Reviewed-by: Andy Polyakov <appro@openssl.org> Reviewed-by: Matt Caswell <matt@openssl.org> (Merged from https://github.com/openssl/openssl/pull/6690)
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int (*ladder_pre)(const EC_GROUP *group,
EC_POINT *r, EC_POINT *s,
EC_POINT *p, BN_CTX *ctx);
int (*ladder_step)(const EC_GROUP *group,
EC_POINT *r, EC_POINT *s,
EC_POINT *p, BN_CTX *ctx);
int (*ladder_post)(const EC_GROUP *group,
EC_POINT *r, EC_POINT *s,
EC_POINT *p, BN_CTX *ctx);
};
/*
* Types and functions to manipulate pre-computed values.
*/
typedef struct nistp224_pre_comp_st NISTP224_PRE_COMP;
typedef struct nistp256_pre_comp_st NISTP256_PRE_COMP;
typedef struct nistp521_pre_comp_st NISTP521_PRE_COMP;
typedef struct nistz256_pre_comp_st NISTZ256_PRE_COMP;
typedef struct ec_pre_comp_st EC_PRE_COMP;
struct ec_group_st {
const EC_METHOD *meth;
EC_POINT *generator; /* optional */
BIGNUM *order, *cofactor;
int curve_name; /* optional NID for named curve */
int asn1_flag; /* flag to control the asn1 encoding */
point_conversion_form_t asn1_form;
unsigned char *seed; /* optional seed for parameters (appears in
* ASN1) */
size_t seed_len;
/*
* The following members are handled by the method functions, even if
* they appear generic
*/
/*
* Field specification. For curves over GF(p), this is the modulus; for
* curves over GF(2^m), this is the irreducible polynomial defining the
* field.
*/
BIGNUM *field;
/*
* Field specification for curves over GF(2^m). The irreducible f(t) is
* then of the form: t^poly[0] + t^poly[1] + ... + t^poly[k] where m =
* poly[0] > poly[1] > ... > poly[k] = 0. The array is terminated with
* poly[k+1]=-1. All elliptic curve irreducibles have at most 5 non-zero
* terms.
*/
int poly[6];
/*
* Curve coefficients. (Here the assumption is that BIGNUMs can be used
* or abused for all kinds of fields, not just GF(p).) For characteristic
* > 3, the curve is defined by a Weierstrass equation of the form y^2 =
* x^3 + a*x + b. For characteristic 2, the curve is defined by an
* equation of the form y^2 + x*y = x^3 + a*x^2 + b.
*/
BIGNUM *a, *b;
/* enable optimized point arithmetics for special case */
int a_is_minus3;
/* method-specific (e.g., Montgomery structure) */
void *field_data1;
/* method-specific */
void *field_data2;
/* method-specific */
int (*field_mod_func) (BIGNUM *, const BIGNUM *, const BIGNUM *,
BN_CTX *);
/* data for ECDSA inverse */
BN_MONT_CTX *mont_data;
/*
* Precomputed values for speed. The PCT_xxx names match the
* pre_comp.xxx union names; see the SETPRECOMP and HAVEPRECOMP
* macros, below.
*/
enum {
PCT_none,
PCT_nistp224, PCT_nistp256, PCT_nistp521, PCT_nistz256,
PCT_ec
} pre_comp_type;
union {
NISTP224_PRE_COMP *nistp224;
NISTP256_PRE_COMP *nistp256;
NISTP521_PRE_COMP *nistp521;
NISTZ256_PRE_COMP *nistz256;
EC_PRE_COMP *ec;
} pre_comp;
};
#define SETPRECOMP(g, type, pre) \
g->pre_comp_type = PCT_##type, g->pre_comp.type = pre
#define HAVEPRECOMP(g, type) \
g->pre_comp_type == PCT_##type && g->pre_comp.type != NULL
struct ec_key_st {
const EC_KEY_METHOD *meth;
ENGINE *engine;
int version;
EC_GROUP *group;
EC_POINT *pub_key;
BIGNUM *priv_key;
unsigned int enc_flag;
point_conversion_form_t conv_form;
CRYPTO_REF_COUNT references;
int flags;
CRYPTO_EX_DATA ex_data;
CRYPTO_RWLOCK *lock;
};
struct ec_point_st {
const EC_METHOD *meth;
/* NID for the curve if known */
int curve_name;
/*
* All members except 'meth' are handled by the method functions, even if
* they appear generic
*/
BIGNUM *X;
BIGNUM *Y;
BIGNUM *Z; /* Jacobian projective coordinates: * (X, Y,
* Z) represents (X/Z^2, Y/Z^3) if Z != 0 */
int Z_is_one; /* enable optimized point arithmetics for
* special case */
};
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static ossl_inline int ec_point_is_compat(const EC_POINT *point,
const EC_GROUP *group)
{
if (group->meth != point->meth
|| (group->curve_name != 0
&& point->curve_name != 0
&& group->curve_name != point->curve_name))
return 0;
return 1;
}
NISTP224_PRE_COMP *EC_nistp224_pre_comp_dup(NISTP224_PRE_COMP *);
NISTP256_PRE_COMP *EC_nistp256_pre_comp_dup(NISTP256_PRE_COMP *);
NISTP521_PRE_COMP *EC_nistp521_pre_comp_dup(NISTP521_PRE_COMP *);
NISTZ256_PRE_COMP *EC_nistz256_pre_comp_dup(NISTZ256_PRE_COMP *);
NISTP256_PRE_COMP *EC_nistp256_pre_comp_dup(NISTP256_PRE_COMP *);
EC_PRE_COMP *EC_ec_pre_comp_dup(EC_PRE_COMP *);
void EC_pre_comp_free(EC_GROUP *group);
void EC_nistp224_pre_comp_free(NISTP224_PRE_COMP *);
void EC_nistp256_pre_comp_free(NISTP256_PRE_COMP *);
void EC_nistp521_pre_comp_free(NISTP521_PRE_COMP *);
void EC_nistz256_pre_comp_free(NISTZ256_PRE_COMP *);
void EC_ec_pre_comp_free(EC_PRE_COMP *);
/*
* method functions in ec_mult.c (ec_lib.c uses these as defaults if
* group->method->mul is 0)
*/
int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *scalar,
size_t num, const EC_POINT *points[], const BIGNUM *scalars[],
BN_CTX *);
int ec_wNAF_precompute_mult(EC_GROUP *group, BN_CTX *);
int ec_wNAF_have_precompute_mult(const EC_GROUP *group);
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/* method functions in ecp_smpl.c */
int ec_GFp_simple_group_init(EC_GROUP *);
void ec_GFp_simple_group_finish(EC_GROUP *);
void ec_GFp_simple_group_clear_finish(EC_GROUP *);
int ec_GFp_simple_group_copy(EC_GROUP *, const EC_GROUP *);
int ec_GFp_simple_group_set_curve(EC_GROUP *, const BIGNUM *p,
const BIGNUM *a, const BIGNUM *b, BN_CTX *);
int ec_GFp_simple_group_get_curve(const EC_GROUP *, BIGNUM *p, BIGNUM *a,
BIGNUM *b, BN_CTX *);
int ec_GFp_simple_group_get_degree(const EC_GROUP *);
int ec_GFp_simple_group_check_discriminant(const EC_GROUP *, BN_CTX *);
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int ec_GFp_simple_point_init(EC_POINT *);
void ec_GFp_simple_point_finish(EC_POINT *);
void ec_GFp_simple_point_clear_finish(EC_POINT *);
int ec_GFp_simple_point_copy(EC_POINT *, const EC_POINT *);
int ec_GFp_simple_point_set_to_infinity(const EC_GROUP *, EC_POINT *);
int ec_GFp_simple_set_Jprojective_coordinates_GFp(const EC_GROUP *,
EC_POINT *, const BIGNUM *x,
const BIGNUM *y,
const BIGNUM *z, BN_CTX *);
int ec_GFp_simple_get_Jprojective_coordinates_GFp(const EC_GROUP *,
const EC_POINT *, BIGNUM *x,
BIGNUM *y, BIGNUM *z,
BN_CTX *);
int ec_GFp_simple_point_set_affine_coordinates(const EC_GROUP *, EC_POINT *,
const BIGNUM *x,
const BIGNUM *y, BN_CTX *);
int ec_GFp_simple_point_get_affine_coordinates(const EC_GROUP *,
const EC_POINT *, BIGNUM *x,
BIGNUM *y, BN_CTX *);
int ec_GFp_simple_set_compressed_coordinates(const EC_GROUP *, EC_POINT *,
const BIGNUM *x, int y_bit,
BN_CTX *);
size_t ec_GFp_simple_point2oct(const EC_GROUP *, const EC_POINT *,
point_conversion_form_t form,
unsigned char *buf, size_t len, BN_CTX *);
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int ec_GFp_simple_oct2point(const EC_GROUP *, EC_POINT *,
const unsigned char *buf, size_t len, BN_CTX *);
int ec_GFp_simple_add(const EC_GROUP *, EC_POINT *r, const EC_POINT *a,
const EC_POINT *b, BN_CTX *);
int ec_GFp_simple_dbl(const EC_GROUP *, EC_POINT *r, const EC_POINT *a,
BN_CTX *);
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int ec_GFp_simple_invert(const EC_GROUP *, EC_POINT *, BN_CTX *);
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int ec_GFp_simple_is_at_infinity(const EC_GROUP *, const EC_POINT *);
int ec_GFp_simple_is_on_curve(const EC_GROUP *, const EC_POINT *, BN_CTX *);
int ec_GFp_simple_cmp(const EC_GROUP *, const EC_POINT *a, const EC_POINT *b,
BN_CTX *);
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int ec_GFp_simple_make_affine(const EC_GROUP *, EC_POINT *, BN_CTX *);
int ec_GFp_simple_points_make_affine(const EC_GROUP *, size_t num,
EC_POINT *[], BN_CTX *);
int ec_GFp_simple_field_mul(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
const BIGNUM *b, BN_CTX *);
int ec_GFp_simple_field_sqr(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
BN_CTX *);
int ec_GFp_simple_blind_coordinates(const EC_GROUP *group, EC_POINT *p,
BN_CTX *ctx);
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/* method functions in ecp_mont.c */
int ec_GFp_mont_group_init(EC_GROUP *);
int ec_GFp_mont_group_set_curve(EC_GROUP *, const BIGNUM *p, const BIGNUM *a,
const BIGNUM *b, BN_CTX *);
void ec_GFp_mont_group_finish(EC_GROUP *);
void ec_GFp_mont_group_clear_finish(EC_GROUP *);
int ec_GFp_mont_group_copy(EC_GROUP *, const EC_GROUP *);
int ec_GFp_mont_field_mul(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
const BIGNUM *b, BN_CTX *);
int ec_GFp_mont_field_sqr(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
BN_CTX *);
int ec_GFp_mont_field_encode(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
BN_CTX *);
int ec_GFp_mont_field_decode(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
BN_CTX *);
int ec_GFp_mont_field_set_to_one(const EC_GROUP *, BIGNUM *r, BN_CTX *);
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/* method functions in ecp_nist.c */
int ec_GFp_nist_group_copy(EC_GROUP *dest, const EC_GROUP *src);
int ec_GFp_nist_group_set_curve(EC_GROUP *, const BIGNUM *p, const BIGNUM *a,
const BIGNUM *b, BN_CTX *);
int ec_GFp_nist_field_mul(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
const BIGNUM *b, BN_CTX *);
int ec_GFp_nist_field_sqr(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
BN_CTX *);
/* method functions in ec2_smpl.c */
int ec_GF2m_simple_group_init(EC_GROUP *);
void ec_GF2m_simple_group_finish(EC_GROUP *);
void ec_GF2m_simple_group_clear_finish(EC_GROUP *);
int ec_GF2m_simple_group_copy(EC_GROUP *, const EC_GROUP *);
int ec_GF2m_simple_group_set_curve(EC_GROUP *, const BIGNUM *p,
const BIGNUM *a, const BIGNUM *b,
BN_CTX *);
int ec_GF2m_simple_group_get_curve(const EC_GROUP *, BIGNUM *p, BIGNUM *a,
BIGNUM *b, BN_CTX *);
int ec_GF2m_simple_group_get_degree(const EC_GROUP *);
int ec_GF2m_simple_group_check_discriminant(const EC_GROUP *, BN_CTX *);
int ec_GF2m_simple_point_init(EC_POINT *);
void ec_GF2m_simple_point_finish(EC_POINT *);
void ec_GF2m_simple_point_clear_finish(EC_POINT *);
int ec_GF2m_simple_point_copy(EC_POINT *, const EC_POINT *);
int ec_GF2m_simple_point_set_to_infinity(const EC_GROUP *, EC_POINT *);
int ec_GF2m_simple_point_set_affine_coordinates(const EC_GROUP *, EC_POINT *,
const BIGNUM *x,
const BIGNUM *y, BN_CTX *);
int ec_GF2m_simple_point_get_affine_coordinates(const EC_GROUP *,
const EC_POINT *, BIGNUM *x,
BIGNUM *y, BN_CTX *);
int ec_GF2m_simple_set_compressed_coordinates(const EC_GROUP *, EC_POINT *,
const BIGNUM *x, int y_bit,
BN_CTX *);
size_t ec_GF2m_simple_point2oct(const EC_GROUP *, const EC_POINT *,
point_conversion_form_t form,
unsigned char *buf, size_t len, BN_CTX *);
int ec_GF2m_simple_oct2point(const EC_GROUP *, EC_POINT *,
const unsigned char *buf, size_t len, BN_CTX *);
int ec_GF2m_simple_add(const EC_GROUP *, EC_POINT *r, const EC_POINT *a,
const EC_POINT *b, BN_CTX *);
int ec_GF2m_simple_dbl(const EC_GROUP *, EC_POINT *r, const EC_POINT *a,
BN_CTX *);
int ec_GF2m_simple_invert(const EC_GROUP *, EC_POINT *, BN_CTX *);
int ec_GF2m_simple_is_at_infinity(const EC_GROUP *, const EC_POINT *);
int ec_GF2m_simple_is_on_curve(const EC_GROUP *, const EC_POINT *, BN_CTX *);
int ec_GF2m_simple_cmp(const EC_GROUP *, const EC_POINT *a, const EC_POINT *b,
BN_CTX *);
int ec_GF2m_simple_make_affine(const EC_GROUP *, EC_POINT *, BN_CTX *);
int ec_GF2m_simple_points_make_affine(const EC_GROUP *, size_t num,
EC_POINT *[], BN_CTX *);
int ec_GF2m_simple_field_mul(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
const BIGNUM *b, BN_CTX *);
int ec_GF2m_simple_field_sqr(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
BN_CTX *);
int ec_GF2m_simple_field_div(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
const BIGNUM *b, BN_CTX *);
#ifndef OPENSSL_NO_EC_NISTP_64_GCC_128
/* method functions in ecp_nistp224.c */
int ec_GFp_nistp224_group_init(EC_GROUP *group);
int ec_GFp_nistp224_group_set_curve(EC_GROUP *group, const BIGNUM *p,
const BIGNUM *a, const BIGNUM *n,
BN_CTX *);
int ec_GFp_nistp224_point_get_affine_coordinates(const EC_GROUP *group,
const EC_POINT *point,
BIGNUM *x, BIGNUM *y,
BN_CTX *ctx);
int ec_GFp_nistp224_mul(const EC_GROUP *group, EC_POINT *r,
const BIGNUM *scalar, size_t num,
const EC_POINT *points[], const BIGNUM *scalars[],
BN_CTX *);
int ec_GFp_nistp224_points_mul(const EC_GROUP *group, EC_POINT *r,
const BIGNUM *scalar, size_t num,
const EC_POINT *points[],
const BIGNUM *scalars[], BN_CTX *ctx);
int ec_GFp_nistp224_precompute_mult(EC_GROUP *group, BN_CTX *ctx);
int ec_GFp_nistp224_have_precompute_mult(const EC_GROUP *group);
/* method functions in ecp_nistp256.c */
int ec_GFp_nistp256_group_init(EC_GROUP *group);
int ec_GFp_nistp256_group_set_curve(EC_GROUP *group, const BIGNUM *p,
const BIGNUM *a, const BIGNUM *n,
BN_CTX *);
int ec_GFp_nistp256_point_get_affine_coordinates(const EC_GROUP *group,
const EC_POINT *point,
BIGNUM *x, BIGNUM *y,
BN_CTX *ctx);
int ec_GFp_nistp256_mul(const EC_GROUP *group, EC_POINT *r,
const BIGNUM *scalar, size_t num,
const EC_POINT *points[], const BIGNUM *scalars[],
BN_CTX *);
int ec_GFp_nistp256_points_mul(const EC_GROUP *group, EC_POINT *r,
const BIGNUM *scalar, size_t num,
const EC_POINT *points[],
const BIGNUM *scalars[], BN_CTX *ctx);
int ec_GFp_nistp256_precompute_mult(EC_GROUP *group, BN_CTX *ctx);
int ec_GFp_nistp256_have_precompute_mult(const EC_GROUP *group);
/* method functions in ecp_nistp521.c */
int ec_GFp_nistp521_group_init(EC_GROUP *group);
int ec_GFp_nistp521_group_set_curve(EC_GROUP *group, const BIGNUM *p,
const BIGNUM *a, const BIGNUM *n,
BN_CTX *);
int ec_GFp_nistp521_point_get_affine_coordinates(const EC_GROUP *group,
const EC_POINT *point,
BIGNUM *x, BIGNUM *y,
BN_CTX *ctx);
int ec_GFp_nistp521_mul(const EC_GROUP *group, EC_POINT *r,
const BIGNUM *scalar, size_t num,
const EC_POINT *points[], const BIGNUM *scalars[],
BN_CTX *);
int ec_GFp_nistp521_points_mul(const EC_GROUP *group, EC_POINT *r,
const BIGNUM *scalar, size_t num,
const EC_POINT *points[],
const BIGNUM *scalars[], BN_CTX *ctx);
int ec_GFp_nistp521_precompute_mult(EC_GROUP *group, BN_CTX *ctx);
int ec_GFp_nistp521_have_precompute_mult(const EC_GROUP *group);
/* utility functions in ecp_nistputil.c */
void ec_GFp_nistp_points_make_affine_internal(size_t num, void *point_array,
size_t felem_size,
void *tmp_felems,
void (*felem_one) (void *out),
int (*felem_is_zero) (const void
*in),
void (*felem_assign) (void *out,
const void
*in),
void (*felem_square) (void *out,
const void
*in),
void (*felem_mul) (void *out,
const void
*in1,
const void
*in2),
void (*felem_inv) (void *out,
const void
*in),
void (*felem_contract) (void
*out,
const
void
*in));
void ec_GFp_nistp_recode_scalar_bits(unsigned char *sign,
unsigned char *digit, unsigned char in);
#endif
int ec_group_simple_order_bits(const EC_GROUP *group);
#ifdef ECP_NISTZ256_ASM
/** Returns GFp methods using montgomery multiplication, with x86-64 optimized
* P256. See http://eprint.iacr.org/2013/816.
* \return EC_METHOD object
*/
const EC_METHOD *EC_GFp_nistz256_method(void);
#endif
size_t ec_key_simple_priv2oct(const EC_KEY *eckey,
unsigned char *buf, size_t len);
int ec_key_simple_oct2priv(EC_KEY *eckey, const unsigned char *buf, size_t len);
int ec_key_simple_generate_key(EC_KEY *eckey);
int ec_key_simple_generate_public_key(EC_KEY *eckey);
int ec_key_simple_check_key(const EC_KEY *eckey);
/* EC_METHOD definitions */
struct ec_key_method_st {
const char *name;
int32_t flags;
int (*init)(EC_KEY *key);
void (*finish)(EC_KEY *key);
int (*copy)(EC_KEY *dest, const EC_KEY *src);
int (*set_group)(EC_KEY *key, const EC_GROUP *grp);
int (*set_private)(EC_KEY *key, const BIGNUM *priv_key);
int (*set_public)(EC_KEY *key, const EC_POINT *pub_key);
int (*keygen)(EC_KEY *key);
int (*compute_key)(unsigned char **pout, size_t *poutlen,
const EC_POINT *pub_key, const EC_KEY *ecdh);
int (*sign)(int type, const unsigned char *dgst, int dlen, unsigned char
*sig, unsigned int *siglen, const BIGNUM *kinv,
const BIGNUM *r, EC_KEY *eckey);
int (*sign_setup)(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
BIGNUM **rp);
ECDSA_SIG *(*sign_sig)(const unsigned char *dgst, int dgst_len,
const BIGNUM *in_kinv, const BIGNUM *in_r,
EC_KEY *eckey);
int (*verify)(int type, const unsigned char *dgst, int dgst_len,
const unsigned char *sigbuf, int sig_len, EC_KEY *eckey);
int (*verify_sig)(const unsigned char *dgst, int dgst_len,
const ECDSA_SIG *sig, EC_KEY *eckey);
};
#define EC_KEY_METHOD_DYNAMIC 1
int ossl_ec_key_gen(EC_KEY *eckey);
int ossl_ecdh_compute_key(unsigned char **pout, size_t *poutlen,
const EC_POINT *pub_key, const EC_KEY *ecdh);
int ecdh_simple_compute_key(unsigned char **pout, size_t *poutlen,
const EC_POINT *pub_key, const EC_KEY *ecdh);
struct ECDSA_SIG_st {
BIGNUM *r;
BIGNUM *s;
};
int ossl_ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
BIGNUM **rp);
int ossl_ecdsa_sign(int type, const unsigned char *dgst, int dlen,
unsigned char *sig, unsigned int *siglen,
const BIGNUM *kinv, const BIGNUM *r, EC_KEY *eckey);
ECDSA_SIG *ossl_ecdsa_sign_sig(const unsigned char *dgst, int dgst_len,
const BIGNUM *in_kinv, const BIGNUM *in_r,
EC_KEY *eckey);
int ossl_ecdsa_verify(int type, const unsigned char *dgst, int dgst_len,
const unsigned char *sigbuf, int sig_len, EC_KEY *eckey);
int ossl_ecdsa_verify_sig(const unsigned char *dgst, int dgst_len,
const ECDSA_SIG *sig, EC_KEY *eckey);
int ED25519_sign(uint8_t *out_sig, const uint8_t *message, size_t message_len,
const uint8_t public_key[32], const uint8_t private_key[32]);
int ED25519_verify(const uint8_t *message, size_t message_len,
const uint8_t signature[64], const uint8_t public_key[32]);
void ED25519_public_from_private(uint8_t out_public_key[32],
const uint8_t private_key[32]);
int X25519(uint8_t out_shared_key[32], const uint8_t private_key[32],
const uint8_t peer_public_value[32]);
void X25519_public_from_private(uint8_t out_public_value[32],
const uint8_t private_key[32]);
/*-
* This functions computes a single point multiplication over the EC group,
* using, at a high level, a Montgomery ladder with conditional swaps, with
* various timing attack defenses.
*
* It performs either a fixed point multiplication
* (scalar * generator)
* when point is NULL, or a variable point multiplication
* (scalar * point)
* when point is not NULL.
*
* `scalar` cannot be NULL and should be in the range [0,n) otherwise all
* constant time bets are off (where n is the cardinality of the EC group).
*
* This function expects `group->order` and `group->cardinality` to be well
* defined and non-zero: it fails with an error code otherwise.
*
* NB: This says nothing about the constant-timeness of the ladder step
* implementation (i.e., the default implementation is based on EC_POINT_add and
* EC_POINT_dbl, which of course are not constant time themselves) or the
* underlying multiprecision arithmetic.
*
* The product is stored in `r`.
*
* This is an internal function: callers are in charge of ensuring that the
* input parameters `group`, `r`, `scalar` and `ctx` are not NULL.
*
* Returns 1 on success, 0 otherwise.
*/
int ec_scalar_mul_ladder(const EC_GROUP *group, EC_POINT *r,
const BIGNUM *scalar, const EC_POINT *point,
BN_CTX *ctx);
int ec_point_blind_coordinates(const EC_GROUP *group, EC_POINT *p, BN_CTX *ctx);
EC point multiplication: add `ladder` scaffold for specialized Montgomery ladder implementations PR #6009 and #6070 replaced the default EC point multiplication path for prime and binary curves with a unified Montgomery ladder implementation with various timing attack defenses (for the common paths when a secret scalar is feed to the point multiplication). The newly introduced default implementation directly used EC_POINT_add/dbl in the main loop. The scaffolding introduced by this commit allows EC_METHODs to define a specialized `ladder_step` function to improve performances by taking advantage of efficient formulas for differential addition-and-doubling and different coordinate systems. - `ladder_pre` is executed before the main loop of the ladder: by default it copies the input point P into S, and doubles it into R. Specialized implementations could, e.g., use this hook to transition to different coordinate systems before copying and doubling; - `ladder_step` is the core of the Montgomery ladder loop: by default it computes `S := R+S; R := 2R;`, but specific implementations could, e.g., implement a more efficient formula for differential addition-and-doubling; - `ladder_post` is executed after the Montgomery ladder loop: by default it's a noop, but specialized implementations could, e.g., use this hook to transition back from the coordinate system used for optimizing the differential addition-and-doubling or recover the y coordinate of the result point. This commit also renames `ec_mul_consttime` to `ec_scalar_mul_ladder`, as it better corresponds to what this function does: nothing can be truly said about the constant-timeness of the overall execution of this function, given that the underlying operations are not necessarily constant-time themselves. What this implementation ensures is that the same fixed sequence of operations is executed for each scalar multiplication (for a given EC_GROUP), with no dependency on the value of the input scalar. Co-authored-by: Sohaib ul Hassan <soh.19.hassan@gmail.com> Co-authored-by: Billy Brumley <bbrumley@gmail.com> Reviewed-by: Andy Polyakov <appro@openssl.org> Reviewed-by: Matt Caswell <matt@openssl.org> (Merged from https://github.com/openssl/openssl/pull/6690)
2018-07-07 21:50:49 +00:00
static inline int ec_point_ladder_pre(const EC_GROUP *group,
EC_POINT *r, EC_POINT *s,
EC_POINT *p, BN_CTX *ctx)
{
if (group->meth->ladder_pre != NULL)
return group->meth->ladder_pre(group, r, s, p, ctx);
if (!EC_POINT_copy(s, p)
|| !EC_POINT_dbl(group, r, s, ctx))
return 0;
return 1;
}
static inline int ec_point_ladder_step(const EC_GROUP *group,
EC_POINT *r, EC_POINT *s,
EC_POINT *p, BN_CTX *ctx)
{
if (group->meth->ladder_step != NULL)
return group->meth->ladder_step(group, r, s, p, ctx);
if (!EC_POINT_add(group, s, r, s, ctx)
|| !EC_POINT_dbl(group, r, r, ctx))
return 0;
return 1;
}
static inline int ec_point_ladder_post(const EC_GROUP *group,
EC_POINT *r, EC_POINT *s,
EC_POINT *p, BN_CTX *ctx)
{
if (group->meth->ladder_post != NULL)
return group->meth->ladder_post(group, r, s, p, ctx);
return 1;
}