ecp_alt.h

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/*
 * Copyright (c) 2001-2019, Arm Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */
#ifndef MBEDTLS_ECP_ALT_H
#define MBEDTLS_ECP_ALT_H
 
#if defined(MBEDTLS_ECP_ALT)
 
#ifdef __cplusplus
extern "C" {
#endif
 
typedef struct mbedtls_ecp_group
{
 mbedtls_ecp_group_id id; 
 mbedtls_mpi P; 
 mbedtls_mpi A; 
 mbedtls_mpi B; 
 mbedtls_ecp_point G; 
 mbedtls_mpi N; 
 size_t pbits; 
 size_t nbits; 
 unsigned int h; 
 int (*modp)(mbedtls_mpi *); 
 int (*t_pre)(mbedtls_ecp_point *, void *); 
 int (*t_post)(mbedtls_ecp_point *, void *); 
 void *t_data; 
 mbedtls_ecp_point *T; 
 size_t T_size; 
}
mbedtls_ecp_group;
 
#if !defined(MBEDTLS_ECP_WINDOW_SIZE)
/*
 * Maximum "window" size used for point multiplication.
 * Default: 6.
 * Minimum value: 2. Maximum value: 7.
 *
 * Result is an array of at most ( 1 << ( MBEDTLS_ECP_WINDOW_SIZE - 1 ) )
 * points used for point multiplication. This value is directly tied to EC
 * peak memory usage, so decreasing it by one should roughly cut memory usage
 * by two (if large curves are in use).
 *
 * Reduction in size may reduce speed, but larger curves are impacted first.
 * Sample performances (in ECDHE handshakes/s, with FIXED_POINT_OPTIM = 1):
 * w-size: 6 5 4 3 2
 * 521 145 141 135 120 97
 * 384 214 209 198 177 146
 * 256 320 320 303 262 226
 * 224 475 475 453 398 342
 * 192 640 640 633 587 476
 */
#define MBEDTLS_ECP_WINDOW_SIZE 6 
#endif /* MBEDTLS_ECP_WINDOW_SIZE */
 
#if !defined(MBEDTLS_ECP_FIXED_POINT_OPTIM)
/*
 * Trade memory for speed on fixed-point multiplication.
 *
 * This speeds up repeated multiplication of the generator (that is, the
 * multiplication in ECDSA signatures, and half of the multiplications in
 * ECDSA verification and ECDHE) by a factor roughly 3 to 4.
 *
 * The cost is increasing EC peak memory usage by a factor roughly 2.
 *
 * Change this value to 0 to reduce peak memory usage.
 */
#define MBEDTLS_ECP_FIXED_POINT_OPTIM 1 
#endif /* MBEDTLS_ECP_FIXED_POINT_OPTIM */
 
/* \} name SECTION: Module settings */
 
#define MBEDTLS_ECP_BUDGET( ops ) /* no-op; for compatibility */
 
#ifdef __cplusplus
}
#endif
 
#endif /* MBEDTLS_ECP_ALT */
 
#endif /* MBEDTLS_ECP_ALT_H */