/src/openssl/crypto/ec/curve448/field.h

Source
/*
 * Copyright 2017-2023 The OpenSSL Project Authors. All Rights Reserved.
 * Copyright 2014 Cryptography Research, Inc.
 *
 * Licensed under the Apache License 2.0 (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
 *
 * Originally written by Mike Hamburg
 */

#ifndef OSSL_CRYPTO_EC_CURVE448_FIELD_H
#define OSSL_CRYPTO_EC_CURVE448_FIELD_H

#include "internal/constant_time.h"
#include <string.h>
#include <assert.h>
#include "word.h"

#define NLIMBS (64 / sizeof(word_t))
#define X_SER_BYTES 56
#define SER_BYTES 56

#if defined(__GNUC__) || defined(__clang__)
#define INLINE_UNUSED __inline__ __attribute__((__unused__, __always_inline__))
#define RESTRICT __restrict__
#define ALIGNED __attribute__((__aligned__(16)))
#else
#define INLINE_UNUSED ossl_inline
#define RESTRICT
#define ALIGNED
#endif

typedef struct gf_s {
    word_t limb[NLIMBS];
} ALIGNED gf_s, gf[1];

/* RFC 7748 support */
#define X_PUBLIC_BYTES X_SER_BYTES
#define X_PRIVATE_BYTES X_PUBLIC_BYTES
#define X_PRIVATE_BITS 448

static INLINE_UNUSED void gf_copy(gf out, const gf a)
{
    *out = *a;
}

static INLINE_UNUSED void gf_add_RAW(gf out, const gf a, const gf b);
static INLINE_UNUSED void gf_sub_RAW(gf out, const gf a, const gf b);
static INLINE_UNUSED void gf_bias(gf inout, int amount);
static INLINE_UNUSED void gf_weak_reduce(gf inout);

void gf_strong_reduce(gf inout);
void gf_add(gf out, const gf a, const gf b);
void gf_sub(gf out, const gf a, const gf b);
void ossl_gf_mul(gf_s *RESTRICT out, const gf a, const gf b);
void ossl_gf_mulw_unsigned(gf_s *RESTRICT out, const gf a, uint32_t b);
void ossl_gf_sqr(gf_s *RESTRICT out, const gf a);
mask_t gf_isr(gf a, const gf x); /** a^2 x = 1, QNR, or 0 if x=0.  Return true if successful */
mask_t gf_eq(const gf x, const gf y);
mask_t gf_lobit(const gf x);
mask_t gf_hibit(const gf x);

void gf_serialize(uint8_t serial[SER_BYTES], const gf x, int with_highbit);
mask_t gf_deserialize(gf x, const uint8_t serial[SER_BYTES], int with_hibit,
    uint8_t hi_nmask);

#define LIMBPERM(i) (i)
#if (ARCH_WORD_BITS == 32)
#include "arch_32/f_impl.h" /* Bring in the inline implementations */
#define LIMB_MASK(i) (((1) << LIMB_PLACE_VALUE(i)) - 1)
#elif (ARCH_WORD_BITS == 64)
#include "arch_64/f_impl.h" /* Bring in the inline implementations */
#define LIMB_MASK(i) (((1ULL) << LIMB_PLACE_VALUE(i)) - 1)
#endif

static const gf ZERO = { { { 0 } } }, ONE = { { { 1 } } };

/* Square x, n times. */
static ossl_inline void gf_sqrn(gf_s *RESTRICT y, const gf x, int n)
{
    gf tmp;

    assert(n > 0);
    if (n & 1) {
        ossl_gf_sqr(y, x);
        n--;
    } else {
        ossl_gf_sqr(tmp, x);
        ossl_gf_sqr(y, tmp);
        n -= 2;
    }
    for (; n; n -= 2) {
        ossl_gf_sqr(tmp, y);
        ossl_gf_sqr(y, tmp);
    }
}

#define gf_add_nr gf_add_RAW

/* Subtract mod p.  Bias by 2 and don't reduce  */
static ossl_inline void gf_sub_nr(gf c, const gf a, const gf b)
{
    gf_sub_RAW(c, a, b);
    gf_bias(c, 2);
    if (GF_HEADROOM < 3)
        gf_weak_reduce(c);
}

/* Subtract mod p. Bias by amt but don't reduce.  */
static ossl_inline void gf_subx_nr(gf c, const gf a, const gf b, int amt)
{
    gf_sub_RAW(c, a, b);
    gf_bias(c, amt);
    if (GF_HEADROOM < amt + 1)
        gf_weak_reduce(c);
}

/* Mul by signed int.  Not constant-time WRT the sign of that int. */
static ossl_inline void gf_mulw(gf c, const gf a, int32_t w)
{
    if (w > 0) {
        ossl_gf_mulw_unsigned(c, a, w);
    } else {
        ossl_gf_mulw_unsigned(c, a, -w);
        gf_sub(c, ZERO, c);
    }
}

/* Constant time, x = is_z ? z : y */
static ossl_inline void gf_cond_sel(gf x, const gf y, const gf z, mask_t is_z)
{
    size_t i;

    for (i = 0; i < NLIMBS; i++) {
#if ARCH_WORD_BITS == 32
        x[0].limb[i] = constant_time_select_32(is_z, z[0].limb[i],
            y[0].limb[i]);
#else
        /* Must be 64 bit */
        x[0].limb[i] = constant_time_select_64(is_z, z[0].limb[i],
            y[0].limb[i]);
#endif
    }
}

/* Constant time, if (neg) x=-x; */
static ossl_inline void gf_cond_neg(gf x, mask_t neg)
{
    gf y;

    gf_sub(y, ZERO, x);
    gf_cond_sel(x, x, y, neg);
}

/* Constant time, if (swap) (x,y) = (y,x); */
static ossl_inline void gf_cond_swap(gf x, gf_s *RESTRICT y, mask_t swap)
{
    size_t i;

    for (i = 0; i < NLIMBS; i++) {
#if ARCH_WORD_BITS == 32
        constant_time_cond_swap_32(swap, &(x[0].limb[i]), &(y->limb[i]));
#else
        /* Must be 64 bit */
        constant_time_cond_swap_64(swap, &(x[0].limb[i]), &(y->limb[i]));
#endif
    }
}

#endif /* OSSL_CRYPTO_EC_CURVE448_FIELD_H */

Line	Count	Source
1		/*
2		* Copyright 2017-2023 The OpenSSL Project Authors. All Rights Reserved.
3		* Copyright 2014 Cryptography Research, Inc.
4		*
5		* Licensed under the Apache License 2.0 (the "License"). You may not use
6		* this file except in compliance with the License. You can obtain a copy
7		* in the file LICENSE in the source distribution or at
8		* https://www.openssl.org/source/license.html
9		*
10		* Originally written by Mike Hamburg
11		*/
12
13		#ifndef OSSL_CRYPTO_EC_CURVE448_FIELD_H
14		#define OSSL_CRYPTO_EC_CURVE448_FIELD_H
15
16		#include "internal/constant_time.h"
17		#include <string.h>
18		#include <assert.h>
19		#include "word.h"
20
21	0	#define NLIMBS (64 / sizeof(word_t))
22	0	#define X_SER_BYTES 56
23	0	#define SER_BYTES 56
24
25		#if defined(__GNUC__) \|\| defined(__clang__)
26		#define INLINE_UNUSED __inline__ __attribute__((__unused__, __always_inline__))
27		#define RESTRICT __restrict__
28		#define ALIGNED __attribute__((__aligned__(16)))
29		#else
30		#define INLINE_UNUSED ossl_inline
31		#define RESTRICT
32		#define ALIGNED
33		#endif
34
35		typedef struct gf_s {
36		word_t limb[NLIMBS];
37		} ALIGNED gf_s, gf[1];
38
39		/* RFC 7748 support */
40	0	#define X_PUBLIC_BYTES X_SER_BYTES
41	0	#define X_PRIVATE_BYTES X_PUBLIC_BYTES
42	0	#define X_PRIVATE_BITS 448
43
44		static INLINE_UNUSED void gf_copy(gf out, const gf a)
45	0	{
46	0	out = a;
47	0	} Unexecuted instantiation: curve448.c:gf_copy Unexecuted instantiation: curve448_tables.c:gf_copy Unexecuted instantiation: eddsa.c:gf_copy Unexecuted instantiation: f_generic.c:gf_copy Unexecuted instantiation: scalar.c:gf_copy Unexecuted instantiation: f_impl64.c:gf_copy
48
49		static INLINE_UNUSED void gf_add_RAW(gf out, const gf a, const gf b);
50		static INLINE_UNUSED void gf_sub_RAW(gf out, const gf a, const gf b);
51		static INLINE_UNUSED void gf_bias(gf inout, int amount);
52		static INLINE_UNUSED void gf_weak_reduce(gf inout);
53
54		void gf_strong_reduce(gf inout);
55		void gf_add(gf out, const gf a, const gf b);
56		void gf_sub(gf out, const gf a, const gf b);
57		void ossl_gf_mul(gf_s *RESTRICT out, const gf a, const gf b);
58		void ossl_gf_mulw_unsigned(gf_s *RESTRICT out, const gf a, uint32_t b);
59		void ossl_gf_sqr(gf_s *RESTRICT out, const gf a);
60		mask_t gf_isr(gf a, const gf x); /** a^2 x = 1, QNR, or 0 if x=0. Return true if successful */
61		mask_t gf_eq(const gf x, const gf y);
62		mask_t gf_lobit(const gf x);
63		mask_t gf_hibit(const gf x);
64
65		void gf_serialize(uint8_t serial[SER_BYTES], const gf x, int with_highbit);
66		mask_t gf_deserialize(gf x, const uint8_t serial[SER_BYTES], int with_hibit,
67		uint8_t hi_nmask);
68
69	0	#define LIMBPERM(i) (i)
70		#if (ARCH_WORD_BITS == 32)
71		#include "arch_32/f_impl.h" /* Bring in the inline implementations */
72		#define LIMB_MASK(i) (((1) << LIMB_PLACE_VALUE(i)) - 1)
73		#elif (ARCH_WORD_BITS == 64)
74		#include "arch_64/f_impl.h" /* Bring in the inline implementations */
75	0	#define LIMB_MASK(i) (((1ULL) << LIMB_PLACE_VALUE(i)) - 1)
76		#endif
77
78		static const gf ZERO = { { { 0 } } }, ONE = { { { 1 } } };
79
80		/* Square x, n times. */
81		static ossl_inline void gf_sqrn(gf_s *RESTRICT y, const gf x, int n)
82	0	{
83	0	gf tmp;
84
85	0	assert(n > 0);
86	0	if (n & 1) {
87	0	ossl_gf_sqr(y, x);
88	0	n--;
89	0	} else {
90	0	ossl_gf_sqr(tmp, x);
91	0	ossl_gf_sqr(y, tmp);
92	0	n -= 2;
93	0	}
94	0	for (; n; n -= 2) {
95	0	ossl_gf_sqr(tmp, y);
96	0	ossl_gf_sqr(y, tmp);
97	0	}
98	0	} Unexecuted instantiation: curve448.c:gf_sqrn Unexecuted instantiation: curve448_tables.c:gf_sqrn Unexecuted instantiation: eddsa.c:gf_sqrn Unexecuted instantiation: f_generic.c:gf_sqrn Unexecuted instantiation: scalar.c:gf_sqrn Unexecuted instantiation: f_impl64.c:gf_sqrn
99
100	0	#define gf_add_nr gf_add_RAW
101
102		/* Subtract mod p. Bias by 2 and don't reduce */
103		static ossl_inline void gf_sub_nr(gf c, const gf a, const gf b)
104	0	{
105	0	gf_sub_RAW(c, a, b);
106	0	gf_bias(c, 2);
107	0	if (GF_HEADROOM < 3)
108	0	gf_weak_reduce(c);
109	0	} Unexecuted instantiation: curve448.c:gf_sub_nr Unexecuted instantiation: curve448_tables.c:gf_sub_nr Unexecuted instantiation: eddsa.c:gf_sub_nr Unexecuted instantiation: f_generic.c:gf_sub_nr Unexecuted instantiation: scalar.c:gf_sub_nr Unexecuted instantiation: f_impl64.c:gf_sub_nr
110
111		/* Subtract mod p. Bias by amt but don't reduce. */
112		static ossl_inline void gf_subx_nr(gf c, const gf a, const gf b, int amt)
113	0	{
114	0	gf_sub_RAW(c, a, b);
115	0	gf_bias(c, amt);
116	0	if (GF_HEADROOM < amt + 1)
117	0	gf_weak_reduce(c);
118	0	} Unexecuted instantiation: curve448.c:gf_subx_nr Unexecuted instantiation: curve448_tables.c:gf_subx_nr Unexecuted instantiation: eddsa.c:gf_subx_nr Unexecuted instantiation: f_generic.c:gf_subx_nr Unexecuted instantiation: scalar.c:gf_subx_nr Unexecuted instantiation: f_impl64.c:gf_subx_nr
119
120		/* Mul by signed int. Not constant-time WRT the sign of that int. */
121		static ossl_inline void gf_mulw(gf c, const gf a, int32_t w)
122	0	{
123	0	if (w > 0) {
124	0	ossl_gf_mulw_unsigned(c, a, w);
125	0	} else {
126	0	ossl_gf_mulw_unsigned(c, a, -w);
127	0	gf_sub(c, ZERO, c);
128	0	}
129	0	} Unexecuted instantiation: curve448.c:gf_mulw Unexecuted instantiation: curve448_tables.c:gf_mulw Unexecuted instantiation: eddsa.c:gf_mulw Unexecuted instantiation: f_generic.c:gf_mulw Unexecuted instantiation: scalar.c:gf_mulw Unexecuted instantiation: f_impl64.c:gf_mulw
130
131		/* Constant time, x = is_z ? z : y */
132		static ossl_inline void gf_cond_sel(gf x, const gf y, const gf z, mask_t is_z)
133	0	{
134	0	size_t i;
135
136	0	for (i = 0; i < NLIMBS; i++) {
137		#if ARCH_WORD_BITS == 32
138		x[0].limb[i] = constant_time_select_32(is_z, z[0].limb[i],
139		y[0].limb[i]);
140		#else
141		/* Must be 64 bit */
142	0	x[0].limb[i] = constant_time_select_64(is_z, z[0].limb[i],
143	0	y[0].limb[i]);
144	0	#endif
145	0	}
146	0	} Unexecuted instantiation: curve448.c:gf_cond_sel Unexecuted instantiation: curve448_tables.c:gf_cond_sel Unexecuted instantiation: eddsa.c:gf_cond_sel Unexecuted instantiation: f_generic.c:gf_cond_sel Unexecuted instantiation: scalar.c:gf_cond_sel Unexecuted instantiation: f_impl64.c:gf_cond_sel
147
148		/* Constant time, if (neg) x=-x; */
149		static ossl_inline void gf_cond_neg(gf x, mask_t neg)
150	0	{
151	0	gf y;
152
153	0	gf_sub(y, ZERO, x);
154	0	gf_cond_sel(x, x, y, neg);
155	0	} Unexecuted instantiation: curve448.c:gf_cond_neg Unexecuted instantiation: curve448_tables.c:gf_cond_neg Unexecuted instantiation: eddsa.c:gf_cond_neg Unexecuted instantiation: f_generic.c:gf_cond_neg Unexecuted instantiation: scalar.c:gf_cond_neg Unexecuted instantiation: f_impl64.c:gf_cond_neg
156
157		/* Constant time, if (swap) (x,y) = (y,x); */
158		static ossl_inline void gf_cond_swap(gf x, gf_s *RESTRICT y, mask_t swap)
159	0	{
160	0	size_t i;
161
162	0	for (i = 0; i < NLIMBS; i++) {
163		#if ARCH_WORD_BITS == 32
164		constant_time_cond_swap_32(swap, &(x[0].limb[i]), &(y->limb[i]));
165		#else
166		/* Must be 64 bit */
167	0	constant_time_cond_swap_64(swap, &(x[0].limb[i]), &(y->limb[i]));
168	0	#endif
169	0	}
170	0	} Unexecuted instantiation: curve448.c:gf_cond_swap Unexecuted instantiation: curve448_tables.c:gf_cond_swap Unexecuted instantiation: eddsa.c:gf_cond_swap Unexecuted instantiation: f_generic.c:gf_cond_swap Unexecuted instantiation: scalar.c:gf_cond_swap Unexecuted instantiation: f_impl64.c:gf_cond_swap
171
172		#endif /* OSSL_CRYPTO_EC_CURVE448_FIELD_H */

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Created: 2025-12-10 06:24