openssl/crypto/ec/curve448/point_448.h
Dr. Matthias St. Pierre fbbfd128c9 Fix header file include guard names
Make the include guards consistent by renaming them systematically according
to the naming conventions below

The public header files (in the 'include/openssl' directory) are not changed
in 1.1.1, because it is a stable release.

For the private header files files, the guard names try to match the path
specified in the include directives, with all letters converted to upper case
and '/' and '.' replaced by '_'. An extra 'OSSL_' is added as prefix.

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9681)
2019-09-27 23:58:12 +02:00

301 lines
9 KiB
C

/*
* Copyright 2017-2019 The OpenSSL Project Authors. All Rights Reserved.
* Copyright 2015-2016 Cryptography Research, Inc.
*
* 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
*
* Originally written by Mike Hamburg
*/
#ifndef OSSL_CRYPTO_EC_CURVE448_POINT_448_H
# define OSSL_CRYPTO_EC_CURVE448_POINT_448_H
# include "curve448utils.h"
# include "field.h"
/* Comb config: number of combs, n, t, s. */
#define COMBS_N 5
#define COMBS_T 5
#define COMBS_S 18
/* Projective Niels coordinates */
typedef struct {
gf a, b, c;
} niels_s, niels_t[1];
typedef struct {
niels_t n;
gf z;
} pniels_t[1];
/* Precomputed base */
struct curve448_precomputed_s {
niels_t table[COMBS_N << (COMBS_T - 1)];
};
# define C448_SCALAR_LIMBS ((446-1)/C448_WORD_BITS+1)
/* The number of bits in a scalar */
# define C448_SCALAR_BITS 446
/* Number of bytes in a serialized scalar. */
# define C448_SCALAR_BYTES 56
/* X448 encoding ratio. */
# define X448_ENCODE_RATIO 2
/* Number of bytes in an x448 public key */
# define X448_PUBLIC_BYTES 56
/* Number of bytes in an x448 private key */
# define X448_PRIVATE_BYTES 56
/* Twisted Edwards extended homogeneous coordinates */
typedef struct curve448_point_s {
gf x, y, z, t;
} curve448_point_t[1];
/* Precomputed table based on a point. Can be trivial implementation. */
struct curve448_precomputed_s;
/* Precomputed table based on a point. Can be trivial implementation. */
typedef struct curve448_precomputed_s curve448_precomputed_s;
/* Scalar is stored packed, because we don't need the speed. */
typedef struct curve448_scalar_s {
c448_word_t limb[C448_SCALAR_LIMBS];
} curve448_scalar_t[1];
/* A scalar equal to 1. */
extern const curve448_scalar_t curve448_scalar_one;
/* A scalar equal to 0. */
extern const curve448_scalar_t curve448_scalar_zero;
/* The identity point on the curve. */
extern const curve448_point_t curve448_point_identity;
/* Precomputed table for the base point on the curve. */
extern const struct curve448_precomputed_s *curve448_precomputed_base;
extern const niels_t *curve448_wnaf_base;
/*
* Read a scalar from wire format or from bytes.
*
* ser (in): Serialized form of a scalar.
* out (out): Deserialized form.
*
* Returns:
* C448_SUCCESS: The scalar was correctly encoded.
* C448_FAILURE: The scalar was greater than the modulus, and has been reduced
* modulo that modulus.
*/
c448_error_t curve448_scalar_decode(curve448_scalar_t out,
const unsigned char ser[C448_SCALAR_BYTES]);
/*
* Read a scalar from wire format or from bytes. Reduces mod scalar prime.
*
* ser (in): Serialized form of a scalar.
* ser_len (in): Length of serialized form.
* out (out): Deserialized form.
*/
void curve448_scalar_decode_long(curve448_scalar_t out,
const unsigned char *ser, size_t ser_len);
/*
* Serialize a scalar to wire format.
*
* ser (out): Serialized form of a scalar.
* s (in): Deserialized scalar.
*/
void curve448_scalar_encode(unsigned char ser[C448_SCALAR_BYTES],
const curve448_scalar_t s);
/*
* Add two scalars. |a|, |b| and |out| may alias each other.
*
* a (in): One scalar.
* b (in): Another scalar.
* out (out): a+b.
*/
void curve448_scalar_add(curve448_scalar_t out,
const curve448_scalar_t a, const curve448_scalar_t b);
/*
* Subtract two scalars. |a|, |b| and |out| may alias each other.
* a (in): One scalar.
* b (in): Another scalar.
* out (out): a-b.
*/
void curve448_scalar_sub(curve448_scalar_t out,
const curve448_scalar_t a, const curve448_scalar_t b);
/*
* Multiply two scalars. |a|, |b| and |out| may alias each other.
*
* a (in): One scalar.
* b (in): Another scalar.
* out (out): a*b.
*/
void curve448_scalar_mul(curve448_scalar_t out,
const curve448_scalar_t a, const curve448_scalar_t b);
/*
* Halve a scalar. |a| and |out| may alias each other.
*
* a (in): A scalar.
* out (out): a/2.
*/
void curve448_scalar_halve(curve448_scalar_t out, const curve448_scalar_t a);
/*
* Copy a scalar. The scalars may alias each other, in which case this
* function does nothing.
*
* a (in): A scalar.
* out (out): Will become a copy of a.
*/
static ossl_inline void curve448_scalar_copy(curve448_scalar_t out,
const curve448_scalar_t a)
{
*out = *a;
}
/*
* Copy a point. The input and output may alias, in which case this function
* does nothing.
*
* a (out): A copy of the point.
* b (in): Any point.
*/
static ossl_inline void curve448_point_copy(curve448_point_t a,
const curve448_point_t b)
{
*a = *b;
}
/*
* Test whether two points are equal. If yes, return C448_TRUE, else return
* C448_FALSE.
*
* a (in): A point.
* b (in): Another point.
*
* Returns:
* C448_TRUE: The points are equal.
* C448_FALSE: The points are not equal.
*/
__owur c448_bool_t curve448_point_eq(const curve448_point_t a,
const curve448_point_t b);
/*
* Double a point. Equivalent to curve448_point_add(two_a,a,a), but potentially
* faster.
*
* two_a (out): The sum a+a.
* a (in): A point.
*/
void curve448_point_double(curve448_point_t two_a, const curve448_point_t a);
/*
* RFC 7748 Diffie-Hellman scalarmul. This function uses a different
* (non-Decaf) encoding.
*
* out (out): The scaled point base*scalar
* base (in): The point to be scaled.
* scalar (in): The scalar to multiply by.
*
* Returns:
* C448_SUCCESS: The scalarmul succeeded.
* C448_FAILURE: The scalarmul didn't succeed, because the base point is in a
* small subgroup.
*/
__owur c448_error_t x448_int(uint8_t out[X448_PUBLIC_BYTES],
const uint8_t base[X448_PUBLIC_BYTES],
const uint8_t scalar[X448_PRIVATE_BYTES]);
/*
* Multiply a point by X448_ENCODE_RATIO, then encode it like RFC 7748.
*
* This function is mainly used internally, but is exported in case
* it will be useful.
*
* The ratio is necessary because the internal representation doesn't
* track the cofactor information, so on output we must clear the cofactor.
* This would multiply by the cofactor, but in fact internally points are always
* even, so it multiplies by half the cofactor instead.
*
* As it happens, this aligns with the base point definitions; that is,
* if you pass the Decaf/Ristretto base point to this function, the result
* will be X448_ENCODE_RATIO times the X448
* base point.
*
* out (out): The scaled and encoded point.
* p (in): The point to be scaled and encoded.
*/
void curve448_point_mul_by_ratio_and_encode_like_x448(
uint8_t out[X448_PUBLIC_BYTES],
const curve448_point_t p);
/*
* RFC 7748 Diffie-Hellman base point scalarmul. This function uses a different
* (non-Decaf) encoding.
*
* out (out): The scaled point base*scalar
* scalar (in): The scalar to multiply by.
*/
void x448_derive_public_key(uint8_t out[X448_PUBLIC_BYTES],
const uint8_t scalar[X448_PRIVATE_BYTES]);
/*
* Multiply a precomputed base point by a scalar: out = scalar*base.
*
* scaled (out): The scaled point base*scalar
* base (in): The point to be scaled.
* scalar (in): The scalar to multiply by.
*/
void curve448_precomputed_scalarmul(curve448_point_t scaled,
const curve448_precomputed_s * base,
const curve448_scalar_t scalar);
/*
* Multiply two base points by two scalars:
* combo = scalar1*curve448_point_base + scalar2*base2.
*
* Otherwise equivalent to curve448_point_double_scalarmul, but may be
* faster at the expense of being variable time.
*
* combo (out): The linear combination scalar1*base + scalar2*base2.
* scalar1 (in): A first scalar to multiply by.
* base2 (in): A second point to be scaled.
* scalar2 (in) A second scalar to multiply by.
*
* Warning: This function takes variable time, and may leak the scalars used.
* It is designed for signature verification.
*/
void curve448_base_double_scalarmul_non_secret(curve448_point_t combo,
const curve448_scalar_t scalar1,
const curve448_point_t base2,
const curve448_scalar_t scalar2);
/*
* Test that a point is valid, for debugging purposes.
*
* to_test (in): The point to test.
*
* Returns:
* C448_TRUE The point is valid.
* C448_FALSE The point is invalid.
*/
__owur c448_bool_t curve448_point_valid(const curve448_point_t to_test);
/* Overwrite scalar with zeros. */
void curve448_scalar_destroy(curve448_scalar_t scalar);
/* Overwrite point with zeros. */
void curve448_point_destroy(curve448_point_t point);
#endif /* OSSL_CRYPTO_EC_CURVE448_POINT_448_H */