ecp.h

Go to the documentation of this file.

/*
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
 *
 *  This file is provided under the Apache License 2.0, or the
 *  GNU General Public License v2.0 or later.
 *
 *  **********
 *  Apache License 2.0:
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  **********
 *
 *  **********
 *  GNU General Public License v2.0 or later:
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 *  **********
 */

#ifndef MBEDTLS_ECP_H
#define MBEDTLS_ECP_H

#if !defined(MBEDTLS_CONFIG_FILE)
#include "config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif

#include "bignum.h"

/*
 * ECP error codes
 */
#define MBEDTLS_ERR_ECP_BAD_INPUT_DATA                    -0x4F80  
#define MBEDTLS_ERR_ECP_BUFFER_TOO_SMALL                  -0x4F00  
#define MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE               -0x4E80  
#define MBEDTLS_ERR_ECP_VERIFY_FAILED                     -0x4E00  
#define MBEDTLS_ERR_ECP_ALLOC_FAILED                      -0x4D80  
#define MBEDTLS_ERR_ECP_RANDOM_FAILED                     -0x4D00  
#define MBEDTLS_ERR_ECP_INVALID_KEY                       -0x4C80  
#define MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH                  -0x4C00  
/* MBEDTLS_ERR_ECP_HW_ACCEL_FAILED is deprecated and should not be used. */
#define MBEDTLS_ERR_ECP_HW_ACCEL_FAILED                   -0x4B80  
#define MBEDTLS_ERR_ECP_IN_PROGRESS                       -0x4B00  
#ifdef __cplusplus
extern "C" {
#endif

typedef enum
{
    MBEDTLS_ECP_DP_NONE = 0,       
    MBEDTLS_ECP_DP_SECP192R1,      
    MBEDTLS_ECP_DP_SECP224R1,      
    MBEDTLS_ECP_DP_SECP256R1,      
    MBEDTLS_ECP_DP_SECP384R1,      
    MBEDTLS_ECP_DP_SECP521R1,      
    MBEDTLS_ECP_DP_BP256R1,        
    MBEDTLS_ECP_DP_BP384R1,        
    MBEDTLS_ECP_DP_BP512R1,        
    MBEDTLS_ECP_DP_CURVE25519,     
    MBEDTLS_ECP_DP_SECP192K1,      
    MBEDTLS_ECP_DP_SECP224K1,      
    MBEDTLS_ECP_DP_SECP256K1,      
    MBEDTLS_ECP_DP_CURVE448,       
} mbedtls_ecp_group_id;

#define MBEDTLS_ECP_DP_MAX     12

typedef struct mbedtls_ecp_curve_info
{
    mbedtls_ecp_group_id grp_id;    
    uint16_t tls_id;                
    uint16_t bit_size;              
    const char *name;               
} mbedtls_ecp_curve_info;

typedef struct mbedtls_ecp_point
{
    mbedtls_mpi X;          
    mbedtls_mpi Y;          
    mbedtls_mpi Z;          
}
mbedtls_ecp_point;

/* Determine the minimum safe value of MBEDTLS_ECP_MAX_BITS. */
#if !defined(MBEDTLS_ECP_C)
#define MBEDTLS_ECP_MAX_BITS_MIN 0
/* Note: the curves must be listed in DECREASING size! */
#elif defined(MBEDTLS_ECP_DP_SECP521R1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS_MIN 521
#elif defined(MBEDTLS_ECP_DP_BP512R1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS_MIN 512
#elif defined(MBEDTLS_ECP_DP_CURVE448_ENABLED)
#define MBEDTLS_ECP_MAX_BITS_MIN 448
#elif defined(MBEDTLS_ECP_DP_BP384R1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS_MIN 384
#elif defined(MBEDTLS_ECP_DP_SECP384R1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS_MIN 384
#elif defined(MBEDTLS_ECP_DP_BP256R1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS_MIN 256
#elif defined(MBEDTLS_ECP_DP_SECP256K1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS_MIN 256
#elif defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS_MIN 256
#elif defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED)
#define MBEDTLS_ECP_MAX_BITS_MIN 255
#elif defined(MBEDTLS_ECP_DP_SECP224K1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS_MIN 225 // n is slightly above 2^224
#elif defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS_MIN 224
#elif defined(MBEDTLS_ECP_DP_SECP192K1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS_MIN 192
#elif defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS_MIN 192
#else
#error "MBEDTLS_ECP_C enabled, but no curve?"
#endif

#if !defined(MBEDTLS_ECP_ALT)
/*
 * default mbed TLS elliptic curve arithmetic implementation
 *
 * (in case MBEDTLS_ECP_ALT is defined then the developer has to provide an
 * alternative implementation for the whole module and it will replace this
 * one.)
 */

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_MAX_BITS)

#if MBEDTLS_ECP_MAX_BITS < MBEDTLS_ECP_MAX_BITS_MIN
#error "MBEDTLS_ECP_MAX_BITS is smaller than the largest supported curve"
#endif

#else

#define MBEDTLS_ECP_MAX_BITS     521   
#endif

#define MBEDTLS_ECP_MAX_BYTES    ( ( MBEDTLS_ECP_MAX_BITS + 7 ) / 8 )
#define MBEDTLS_ECP_MAX_PT_LEN   ( 2 * MBEDTLS_ECP_MAX_BYTES + 1 )

#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 */

#else  /* MBEDTLS_ECP_ALT */
#include "ecp_alt.h"
#endif /* MBEDTLS_ECP_ALT */

#if defined(MBEDTLS_ECP_RESTARTABLE)

typedef struct mbedtls_ecp_restart_mul mbedtls_ecp_restart_mul_ctx;

typedef struct mbedtls_ecp_restart_muladd mbedtls_ecp_restart_muladd_ctx;

typedef struct
{
    unsigned ops_done;                  
    unsigned depth;                     
    mbedtls_ecp_restart_mul_ctx *rsm;   
    mbedtls_ecp_restart_muladd_ctx *ma; 
} mbedtls_ecp_restart_ctx;

/*
 * Operation counts for restartable functions
 */
#define MBEDTLS_ECP_OPS_CHK   3 
#define MBEDTLS_ECP_OPS_DBL   8 
#define MBEDTLS_ECP_OPS_ADD  11 
#define MBEDTLS_ECP_OPS_INV 120 
int mbedtls_ecp_check_budget( const mbedtls_ecp_group *grp,
                              mbedtls_ecp_restart_ctx *rs_ctx,
                              unsigned ops );

/* Utility macro for checking and updating ops budget */
#define MBEDTLS_ECP_BUDGET( ops )   \
    MBEDTLS_MPI_CHK( mbedtls_ecp_check_budget( grp, rs_ctx, \
                                               (unsigned) (ops) ) );

#else /* MBEDTLS_ECP_RESTARTABLE */

#define MBEDTLS_ECP_BUDGET( ops )   /* no-op; for compatibility */

/* We want to declare restartable versions of existing functions anyway */
typedef void mbedtls_ecp_restart_ctx;

#endif /* MBEDTLS_ECP_RESTARTABLE */

typedef struct mbedtls_ecp_keypair
{
    mbedtls_ecp_group grp;      
    mbedtls_mpi d;              
    mbedtls_ecp_point Q;        
}
mbedtls_ecp_keypair;

/*
 * Point formats, from RFC 4492's enum ECPointFormat
 */
#define MBEDTLS_ECP_PF_UNCOMPRESSED    0   
#define MBEDTLS_ECP_PF_COMPRESSED      1   
/*
 * Some other constants from RFC 4492
 */
#define MBEDTLS_ECP_TLS_NAMED_CURVE    3   
#if defined(MBEDTLS_ECP_RESTARTABLE)

void mbedtls_ecp_set_max_ops( unsigned max_ops );

int mbedtls_ecp_restart_is_enabled( void );
#endif /* MBEDTLS_ECP_RESTARTABLE */

const mbedtls_ecp_curve_info *mbedtls_ecp_curve_list( void );

const mbedtls_ecp_group_id *mbedtls_ecp_grp_id_list( void );

const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_grp_id( mbedtls_ecp_group_id grp_id );

const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_tls_id( uint16_t tls_id );

const mbedtls_ecp_curve_info *mbedtls_ecp_curve_info_from_name( const char *name );

void mbedtls_ecp_point_init( mbedtls_ecp_point *pt );

void mbedtls_ecp_group_init( mbedtls_ecp_group *grp );

void mbedtls_ecp_keypair_init( mbedtls_ecp_keypair *key );

void mbedtls_ecp_point_free( mbedtls_ecp_point *pt );

void mbedtls_ecp_group_free( mbedtls_ecp_group *grp );

void mbedtls_ecp_keypair_free( mbedtls_ecp_keypair *key );

#if defined(MBEDTLS_ECP_RESTARTABLE)

void mbedtls_ecp_restart_init( mbedtls_ecp_restart_ctx *ctx );

void mbedtls_ecp_restart_free( mbedtls_ecp_restart_ctx *ctx );
#endif /* MBEDTLS_ECP_RESTARTABLE */

int mbedtls_ecp_copy( mbedtls_ecp_point *P, const mbedtls_ecp_point *Q );

int mbedtls_ecp_group_copy( mbedtls_ecp_group *dst,
                            const mbedtls_ecp_group *src );

int mbedtls_ecp_set_zero( mbedtls_ecp_point *pt );

int mbedtls_ecp_is_zero( mbedtls_ecp_point *pt );

int mbedtls_ecp_point_cmp( const mbedtls_ecp_point *P,
                           const mbedtls_ecp_point *Q );

int mbedtls_ecp_point_read_string( mbedtls_ecp_point *P, int radix,
                           const char *x, const char *y );

int mbedtls_ecp_point_write_binary( const mbedtls_ecp_group *grp, const mbedtls_ecp_point *P,
                            int format, size_t *olen,
                            unsigned char *buf, size_t buflen );

int mbedtls_ecp_point_read_binary( const mbedtls_ecp_group *grp,
                                   mbedtls_ecp_point *P,
                                   const unsigned char *buf, size_t ilen );

int mbedtls_ecp_tls_read_point( const mbedtls_ecp_group *grp,
                                mbedtls_ecp_point *pt,
                                const unsigned char **buf, size_t len );

int mbedtls_ecp_tls_write_point( const mbedtls_ecp_group *grp,
                                 const mbedtls_ecp_point *pt,
                                 int format, size_t *olen,
                                 unsigned char *buf, size_t blen );

int mbedtls_ecp_group_load( mbedtls_ecp_group *grp, mbedtls_ecp_group_id id );

int mbedtls_ecp_tls_read_group( mbedtls_ecp_group *grp,
                                const unsigned char **buf, size_t len );

int mbedtls_ecp_tls_read_group_id( mbedtls_ecp_group_id *grp,
                                   const unsigned char **buf,
                                   size_t len );
int mbedtls_ecp_tls_write_group( const mbedtls_ecp_group *grp,
                                 size_t *olen,
                                 unsigned char *buf, size_t blen );

int mbedtls_ecp_mul( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
             const mbedtls_mpi *m, const mbedtls_ecp_point *P,
             int (*f_rng)(void *, unsigned char *, size_t), void *p_rng );

int mbedtls_ecp_mul_restartable( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
             const mbedtls_mpi *m, const mbedtls_ecp_point *P,
             int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
             mbedtls_ecp_restart_ctx *rs_ctx );

int mbedtls_ecp_muladd( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
             const mbedtls_mpi *m, const mbedtls_ecp_point *P,
             const mbedtls_mpi *n, const mbedtls_ecp_point *Q );

int mbedtls_ecp_muladd_restartable(
             mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
             const mbedtls_mpi *m, const mbedtls_ecp_point *P,
             const mbedtls_mpi *n, const mbedtls_ecp_point *Q,
             mbedtls_ecp_restart_ctx *rs_ctx );

int mbedtls_ecp_check_pubkey( const mbedtls_ecp_group *grp,
                              const mbedtls_ecp_point *pt );

int mbedtls_ecp_check_privkey( const mbedtls_ecp_group *grp,
                               const mbedtls_mpi *d );

int mbedtls_ecp_gen_privkey( const mbedtls_ecp_group *grp,
                     mbedtls_mpi *d,
                     int (*f_rng)(void *, unsigned char *, size_t),
                     void *p_rng );

int mbedtls_ecp_gen_keypair_base( mbedtls_ecp_group *grp,
                                  const mbedtls_ecp_point *G,
                                  mbedtls_mpi *d, mbedtls_ecp_point *Q,
                                  int (*f_rng)(void *, unsigned char *, size_t),
                                  void *p_rng );

int mbedtls_ecp_gen_keypair( mbedtls_ecp_group *grp, mbedtls_mpi *d,
                             mbedtls_ecp_point *Q,
                             int (*f_rng)(void *, unsigned char *, size_t),
                             void *p_rng );

int mbedtls_ecp_gen_key( mbedtls_ecp_group_id grp_id, mbedtls_ecp_keypair *key,
                         int (*f_rng)(void *, unsigned char *, size_t),
                         void *p_rng );

int mbedtls_ecp_check_pub_priv( const mbedtls_ecp_keypair *pub,
                                const mbedtls_ecp_keypair *prv );

#if defined(MBEDTLS_SELF_TEST)

int mbedtls_ecp_self_test( int verbose );

#endif /* MBEDTLS_SELF_TEST */

#ifdef __cplusplus
}
#endif

#endif /* ecp.h */