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
 */
 
#ifndef MBEDTLS_ECP_H
#define MBEDTLS_ECP_H
#include "mbedtls/private_access.h"
 
#include "mbedtls/build_info.h"
#include "mbedtls/platform_util.h"
 
#include "mbedtls/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
#define MBEDTLS_ERR_ECP_IN_PROGRESS                       -0x4B00
 
/* Flags indicating whether to include code that is specific to certain
 * types of curves. These flags are for internal library use only. */
#if defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED) || \
    defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED) || \
    defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED) || \
    defined(MBEDTLS_ECP_DP_SECP384R1_ENABLED) || \
    defined(MBEDTLS_ECP_DP_SECP521R1_ENABLED) || \
    defined(MBEDTLS_ECP_DP_BP256R1_ENABLED) || \
    defined(MBEDTLS_ECP_DP_BP384R1_ENABLED) || \
    defined(MBEDTLS_ECP_DP_BP512R1_ENABLED) || \
    defined(MBEDTLS_ECP_DP_SECP192K1_ENABLED) || \
    defined(MBEDTLS_ECP_DP_SECP224K1_ENABLED) || \
    defined(MBEDTLS_ECP_DP_SECP256K1_ENABLED)
#define MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED
#endif
#if defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED) || \
    defined(MBEDTLS_ECP_DP_CURVE448_ENABLED)
#define MBEDTLS_ECP_MONTGOMERY_ENABLED
#endif
 
#ifdef __cplusplus
extern "C" {
#endif
 
/* Note: when adding a new curve:
 * - Add it at the end of this enum, otherwise you'll break the ABI by
 *   changing the numerical value for existing curves.
 * - Increment MBEDTLS_ECP_DP_MAX below if needed.
 * - Update the calculation of MBEDTLS_ECP_MAX_BITS below.
 * - Add the corresponding MBEDTLS_ECP_DP_xxx_ENABLED macro definition to
 *   mbedtls_config.h.
 * - List the curve as a dependency of MBEDTLS_ECP_C and
 *   MBEDTLS_ECDSA_C if supported in check_config.h.
 * - Add the curve to the appropriate curve type macro
 *   MBEDTLS_ECP_yyy_ENABLED above.
 * - Add the necessary definitions to ecp_curves.c.
 * - Add the curve to the ecp_supported_curves array in ecp.c.
 * - Add the curve to applicable profiles in x509_crt.c.
 * - Add the curve to applicable presets in ssl_tls.c.
 */
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     14
 
/*
 * Curve types
 */
typedef enum {
    MBEDTLS_ECP_TYPE_NONE = 0,
    MBEDTLS_ECP_TYPE_SHORT_WEIERSTRASS,    /* y^2 = x^3 + a x + b      */
    MBEDTLS_ECP_TYPE_MONTGOMERY,           /* y^2 = x^3 + a x^2 + x    */
} mbedtls_ecp_curve_type;
 
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 MBEDTLS_PRIVATE(X);          
    mbedtls_mpi MBEDTLS_PRIVATE(Y);          
    mbedtls_mpi MBEDTLS_PRIVATE(Z);          
}
mbedtls_ecp_point;
 
#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;               
    /* End of public fields */
 
    unsigned int MBEDTLS_PRIVATE(h);             
    int(*MBEDTLS_PRIVATE(modp))(mbedtls_mpi *);  
    int(*MBEDTLS_PRIVATE(t_pre))(mbedtls_ecp_point *, void *);   
    int(*MBEDTLS_PRIVATE(t_post))(mbedtls_ecp_point *, void *);  
    void *MBEDTLS_PRIVATE(t_data);               
    mbedtls_ecp_point *MBEDTLS_PRIVATE(T);       
    size_t MBEDTLS_PRIVATE(T_size);              
}
mbedtls_ecp_group;
 
#if !defined(MBEDTLS_ECP_WINDOW_SIZE)
/*
 * Maximum "window" size used for point multiplication.
 * Default: a point where higher memory usage yields diminishing performance
 *          returns.
 * 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    4   
#endif /* MBEDTLS_ECP_WINDOW_SIZE */
 
#if !defined(MBEDTLS_ECP_FIXED_POINT_OPTIM)
/*
 * Trade code size 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.
 *
 * For each n-bit Short Weierstrass curve that is enabled, this adds 4n bytes
 * of code size if n < 384 and 8n otherwise.
 *
 * Change this value to 0 to reduce code size.
 */
#define MBEDTLS_ECP_FIXED_POINT_OPTIM  1   
#endif /* MBEDTLS_ECP_FIXED_POINT_OPTIM */
 
#else  /* MBEDTLS_ECP_ALT */
#include "ecp_alt.h"
#endif /* MBEDTLS_ECP_ALT */
 
#if !defined(MBEDTLS_ECP_LIGHT)
/* Dummy definition to help code that has optional ECP support and
 * defines an MBEDTLS_ECP_MAX_BYTES-sized array unconditionally. */
#define MBEDTLS_ECP_MAX_BITS 1
/* Note: the curves must be listed in DECREASING size! */
#elif defined(MBEDTLS_ECP_DP_SECP521R1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS 521
#elif defined(MBEDTLS_ECP_DP_BP512R1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS 512
#elif defined(MBEDTLS_ECP_DP_CURVE448_ENABLED)
#define MBEDTLS_ECP_MAX_BITS 448
#elif defined(MBEDTLS_ECP_DP_BP384R1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS 384
#elif defined(MBEDTLS_ECP_DP_SECP384R1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS 384
#elif defined(MBEDTLS_ECP_DP_BP256R1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS 256
#elif defined(MBEDTLS_ECP_DP_SECP256K1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS 256
#elif defined(MBEDTLS_ECP_DP_SECP256R1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS 256
#elif defined(MBEDTLS_ECP_DP_CURVE25519_ENABLED)
#define MBEDTLS_ECP_MAX_BITS 255
#elif defined(MBEDTLS_ECP_DP_SECP224K1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS 225 // n is slightly above 2^224
#elif defined(MBEDTLS_ECP_DP_SECP224R1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS 224
#elif defined(MBEDTLS_ECP_DP_SECP192K1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS 192
#elif defined(MBEDTLS_ECP_DP_SECP192R1_ENABLED)
#define MBEDTLS_ECP_MAX_BITS 192
#else /* !MBEDTLS_ECP_LIGHT */
#error "Missing definition of MBEDTLS_ECP_MAX_BITS"
#endif /* !MBEDTLS_ECP_LIGHT */
 
#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_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 MBEDTLS_PRIVATE(ops_done);                  
    unsigned MBEDTLS_PRIVATE(depth);                     
    mbedtls_ecp_restart_mul_ctx *MBEDTLS_PRIVATE(rsm);   
    mbedtls_ecp_restart_muladd_ctx *MBEDTLS_PRIVATE(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 MBEDTLS_PRIVATE(grp);      
    mbedtls_mpi MBEDTLS_PRIVATE(d);              
    mbedtls_ecp_point MBEDTLS_PRIVATE(Q);        
}
mbedtls_ecp_keypair;
 
#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 */
 
/*
 * Get the type of a curve
 */
mbedtls_ecp_curve_type mbedtls_ecp_get_type(const mbedtls_ecp_group *grp);
 
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,
                    mbedtls_f_rng_t *f_rng, 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,
                                mbedtls_f_rng_t *f_rng, void *p_rng,
                                mbedtls_ecp_restart_ctx *rs_ctx);
 
#if defined(MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED)
static inline int mbedtls_ecp_group_a_is_minus_3(const mbedtls_ecp_group *grp)
{
    return grp->A.MBEDTLS_PRIVATE(p) == NULL;
}
 
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);
#endif /* MBEDTLS_ECP_SHORT_WEIERSTRASS_ENABLED */
 
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,
                            mbedtls_f_rng_t *f_rng,
                            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,
                                 mbedtls_f_rng_t *f_rng,
                                 void *p_rng);
 
int mbedtls_ecp_gen_keypair(mbedtls_ecp_group *grp, mbedtls_mpi *d,
                            mbedtls_ecp_point *Q,
                            mbedtls_f_rng_t *f_rng,
                            void *p_rng);
 
int mbedtls_ecp_gen_key(mbedtls_ecp_group_id grp_id, mbedtls_ecp_keypair *key,
                        mbedtls_f_rng_t *f_rng,
                        void *p_rng);
 
int mbedtls_ecp_set_public_key(mbedtls_ecp_group_id grp_id,
                               mbedtls_ecp_keypair *key,
                               const mbedtls_ecp_point *Q);
 
int mbedtls_ecp_read_key(mbedtls_ecp_group_id grp_id, mbedtls_ecp_keypair *key,
                         const unsigned char *buf, size_t buflen);
 
#if !defined(MBEDTLS_DEPRECATED_REMOVED)
int MBEDTLS_DEPRECATED mbedtls_ecp_write_key(mbedtls_ecp_keypair *key,
                                             unsigned char *buf, size_t buflen);
#endif /* MBEDTLS_DEPRECATED_REMOVED */
 
int mbedtls_ecp_write_key_ext(const mbedtls_ecp_keypair *key,
                              size_t *olen, unsigned char *buf, size_t buflen);
 
int mbedtls_ecp_write_public_key(const mbedtls_ecp_keypair *key,
                                 int format, size_t *olen,
                                 unsigned char *buf, size_t buflen);
 
int mbedtls_ecp_check_pub_priv(
    const mbedtls_ecp_keypair *pub, const mbedtls_ecp_keypair *prv,
    mbedtls_f_rng_t *f_rng, void *p_rng);
 
int mbedtls_ecp_keypair_calc_public(
    mbedtls_ecp_keypair *key,
    mbedtls_f_rng_t *f_rng, void *p_rng);
 
mbedtls_ecp_group_id mbedtls_ecp_keypair_get_group_id(
    const mbedtls_ecp_keypair *key);
 
int mbedtls_ecp_export(const mbedtls_ecp_keypair *key, mbedtls_ecp_group *grp,
                       mbedtls_mpi *d, mbedtls_ecp_point *Q);
 
#if defined(MBEDTLS_SELF_TEST)
 
int mbedtls_ecp_self_test(int verbose);
 
#endif /* MBEDTLS_SELF_TEST */
 
#ifdef __cplusplus
}
#endif
 
#endif /* ecp.h */