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      1 /* Originally written by Bodo Moeller for the OpenSSL project.
      2  * ====================================================================
      3  * Copyright (c) 1998-2005 The OpenSSL Project.  All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  *
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  *
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in
     14  *    the documentation and/or other materials provided with the
     15  *    distribution.
     16  *
     17  * 3. All advertising materials mentioning features or use of this
     18  *    software must display the following acknowledgment:
     19  *    "This product includes software developed by the OpenSSL Project
     20  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
     21  *
     22  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
     23  *    endorse or promote products derived from this software without
     24  *    prior written permission. For written permission, please contact
     25  *    openssl-core (at) openssl.org.
     26  *
     27  * 5. Products derived from this software may not be called "OpenSSL"
     28  *    nor may "OpenSSL" appear in their names without prior written
     29  *    permission of the OpenSSL Project.
     30  *
     31  * 6. Redistributions of any form whatsoever must retain the following
     32  *    acknowledgment:
     33  *    "This product includes software developed by the OpenSSL Project
     34  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
     35  *
     36  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
     37  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     38  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     39  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
     40  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     41  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     42  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     43  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     44  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
     45  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     46  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
     47  * OF THE POSSIBILITY OF SUCH DAMAGE.
     48  * ====================================================================
     49  *
     50  * This product includes cryptographic software written by Eric Young
     51  * (eay (at) cryptsoft.com).  This product includes software written by Tim
     52  * Hudson (tjh (at) cryptsoft.com).
     53  *
     54  */
     55 /* ====================================================================
     56  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
     57  *
     58  * Portions of the attached software ("Contribution") are developed by
     59  * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
     60  *
     61  * The Contribution is licensed pursuant to the OpenSSL open source
     62  * license provided above.
     63  *
     64  * The elliptic curve binary polynomial software is originally written by
     65  * Sheueling Chang Shantz and Douglas Stebila of Sun Microsystems
     66  * Laboratories. */
     67 
     68 #ifndef OPENSSL_HEADER_EC_INTERNAL_H
     69 #define OPENSSL_HEADER_EC_INTERNAL_H
     70 
     71 #include <openssl/base.h>
     72 
     73 #include <openssl/bn.h>
     74 #include <openssl/ex_data.h>
     75 #include <openssl/thread.h>
     76 
     77 #if defined(__cplusplus)
     78 extern "C" {
     79 #endif
     80 
     81 
     82 struct ec_method_st {
     83   /* used by EC_GROUP_new, EC_GROUP_free, EC_GROUP_clear_free, EC_GROUP_copy: */
     84   int (*group_init)(EC_GROUP *);
     85   void (*group_finish)(EC_GROUP *);
     86   void (*group_clear_finish)(EC_GROUP *);
     87   int (*group_copy)(EC_GROUP *, const EC_GROUP *);
     88 
     89   /* used by EC_GROUP_set_curve_GFp, EC_GROUP_get_curve_GFp, */
     90   /* EC_GROUP_set_curve_GF2m, and EC_GROUP_get_curve_GF2m: */
     91   int (*group_set_curve)(EC_GROUP *, const BIGNUM *p, const BIGNUM *a,
     92                          const BIGNUM *b, BN_CTX *);
     93 
     94   /* used by EC_POINT_get_affine_coordinates_GFp: */
     95   int (*point_get_affine_coordinates)(const EC_GROUP *, const EC_POINT *,
     96                                       BIGNUM *x, BIGNUM *y, BN_CTX *);
     97 
     98   /* Computes |r = g_scalar*generator + p_scalar*p| if |g_scalar| and |p_scalar|
     99    * are both non-null. Computes |r = g_scalar*generator| if |p_scalar| is null.
    100    * Computes |r = p_scalar*p| if g_scalar is null. At least one of |g_scalar|
    101    * and |p_scalar| must be non-null, and |p| must be non-null if |p_scalar| is
    102    * non-null. */
    103   int (*mul)(const EC_GROUP *group, EC_POINT *r, const BIGNUM *g_scalar,
    104              const EC_POINT *p, const BIGNUM *p_scalar, BN_CTX *ctx);
    105 
    106   /* |check_pub_key_order| checks that the public key is in the proper subgroup
    107    * by checking that |pub_key*group->order| is the point at infinity. This may
    108    * be NULL for |EC_METHOD|s specialized for prime-order curves (i.e. with
    109    * cofactor one), as this check is not necessary for such curves (See section
    110    * A.3 of the NSA's "Suite B Implementer's Guide to FIPS 186-3
    111    * (ECDSA)"). */
    112   int (*check_pub_key_order)(const EC_GROUP *group, const EC_POINT *pub_key,
    113                              BN_CTX *ctx);
    114 
    115   /* internal functions */
    116 
    117   /* 'field_mul' and 'field_sqr' can be used by 'add' and 'dbl' so that the
    118    * same implementations of point operations can be used with different
    119    * optimized implementations of expensive field operations: */
    120   int (*field_mul)(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
    121                    const BIGNUM *b, BN_CTX *);
    122   int (*field_sqr)(const EC_GROUP *, BIGNUM *r, const BIGNUM *a, BN_CTX *);
    123 
    124   int (*field_encode)(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
    125                       BN_CTX *); /* e.g. to Montgomery */
    126   int (*field_decode)(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
    127                       BN_CTX *); /* e.g. from Montgomery */
    128   int (*field_set_to_one)(const EC_GROUP *, BIGNUM *r, BN_CTX *);
    129 } /* EC_METHOD */;
    130 
    131 const EC_METHOD* EC_GFp_mont_method(void);
    132 
    133 struct ec_group_st {
    134   const EC_METHOD *meth;
    135 
    136   EC_POINT *generator; /* optional */
    137   BIGNUM order, cofactor;
    138 
    139   int curve_name; /* optional NID for named curve */
    140 
    141   const BN_MONT_CTX *mont_data; /* data for ECDSA inverse */
    142 
    143   /* The following members are handled by the method functions,
    144    * even if they appear generic */
    145 
    146   BIGNUM field; /* For curves over GF(p), this is the modulus. */
    147 
    148   BIGNUM a, b; /* Curve coefficients. */
    149 
    150   int a_is_minus3; /* enable optimized point arithmetics for special case */
    151 
    152   BN_MONT_CTX *mont; /* Montgomery structure. */
    153   BIGNUM *one; /* The value one */
    154 } /* EC_GROUP */;
    155 
    156 struct ec_point_st {
    157   const EC_METHOD *meth;
    158 
    159   /* All members except 'meth' are handled by the method functions,
    160    * even if they appear generic */
    161 
    162   BIGNUM X;
    163   BIGNUM Y;
    164   BIGNUM Z; /* Jacobian projective coordinates:
    165              * (X, Y, Z)  represents  (X/Z^2, Y/Z^3)  if  Z != 0 */
    166   int Z_is_one; /* enable optimized point arithmetics for special case */
    167 } /* EC_POINT */;
    168 
    169 EC_GROUP *ec_group_new(const EC_METHOD *meth);
    170 int ec_group_copy(EC_GROUP *dest, const EC_GROUP *src);
    171 
    172 /* ec_group_get_mont_data returns a Montgomery context for operations in the
    173  * scalar field of |group|. It may return NULL in the case that |group| is not
    174  * a built-in group. */
    175 const BN_MONT_CTX *ec_group_get_mont_data(const EC_GROUP *group);
    176 
    177 int ec_wNAF_mul(const EC_GROUP *group, EC_POINT *r, const BIGNUM *g_scalar,
    178                 const EC_POINT *p, const BIGNUM *p_scalar, BN_CTX *ctx);
    179 
    180 /* method functions in simple.c */
    181 int ec_GFp_simple_group_init(EC_GROUP *);
    182 void ec_GFp_simple_group_finish(EC_GROUP *);
    183 void ec_GFp_simple_group_clear_finish(EC_GROUP *);
    184 int ec_GFp_simple_group_copy(EC_GROUP *, const EC_GROUP *);
    185 int ec_GFp_simple_group_set_curve(EC_GROUP *, const BIGNUM *p, const BIGNUM *a,
    186                                   const BIGNUM *b, BN_CTX *);
    187 int ec_GFp_simple_group_get_curve(const EC_GROUP *, BIGNUM *p, BIGNUM *a,
    188                                   BIGNUM *b, BN_CTX *);
    189 unsigned ec_GFp_simple_group_get_degree(const EC_GROUP *);
    190 int ec_GFp_simple_group_check_discriminant(const EC_GROUP *, BN_CTX *);
    191 int ec_GFp_simple_point_init(EC_POINT *);
    192 void ec_GFp_simple_point_finish(EC_POINT *);
    193 void ec_GFp_simple_point_clear_finish(EC_POINT *);
    194 int ec_GFp_simple_point_copy(EC_POINT *, const EC_POINT *);
    195 int ec_GFp_simple_point_set_to_infinity(const EC_GROUP *, EC_POINT *);
    196 int ec_GFp_simple_set_Jprojective_coordinates_GFp(const EC_GROUP *, EC_POINT *,
    197                                                   const BIGNUM *x,
    198                                                   const BIGNUM *y,
    199                                                   const BIGNUM *z, BN_CTX *);
    200 int ec_GFp_simple_get_Jprojective_coordinates_GFp(const EC_GROUP *,
    201                                                   const EC_POINT *, BIGNUM *x,
    202                                                   BIGNUM *y, BIGNUM *z,
    203                                                   BN_CTX *);
    204 int ec_GFp_simple_point_set_affine_coordinates(const EC_GROUP *, EC_POINT *,
    205                                                const BIGNUM *x, const BIGNUM *y,
    206                                                BN_CTX *);
    207 int ec_GFp_simple_point_get_affine_coordinates(const EC_GROUP *,
    208                                                const EC_POINT *, BIGNUM *x,
    209                                                BIGNUM *y, BN_CTX *);
    210 int ec_GFp_simple_set_compressed_coordinates(const EC_GROUP *, EC_POINT *,
    211                                              const BIGNUM *x, int y_bit,
    212                                              BN_CTX *);
    213 int ec_GFp_simple_add(const EC_GROUP *, EC_POINT *r, const EC_POINT *a,
    214                       const EC_POINT *b, BN_CTX *);
    215 int ec_GFp_simple_dbl(const EC_GROUP *, EC_POINT *r, const EC_POINT *a,
    216                       BN_CTX *);
    217 int ec_GFp_simple_invert(const EC_GROUP *, EC_POINT *, BN_CTX *);
    218 int ec_GFp_simple_is_at_infinity(const EC_GROUP *, const EC_POINT *);
    219 int ec_GFp_simple_is_on_curve(const EC_GROUP *, const EC_POINT *, BN_CTX *);
    220 int ec_GFp_simple_cmp(const EC_GROUP *, const EC_POINT *a, const EC_POINT *b,
    221                       BN_CTX *);
    222 int ec_GFp_simple_make_affine(const EC_GROUP *, EC_POINT *, BN_CTX *);
    223 int ec_GFp_simple_points_make_affine(const EC_GROUP *, size_t num,
    224                                      EC_POINT * [], BN_CTX *);
    225 int ec_GFp_simple_field_mul(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
    226                             const BIGNUM *b, BN_CTX *);
    227 int ec_GFp_simple_field_sqr(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
    228                             BN_CTX *);
    229 
    230 /* method functions in montgomery.c */
    231 int ec_GFp_mont_group_init(EC_GROUP *);
    232 int ec_GFp_mont_group_set_curve(EC_GROUP *, const BIGNUM *p, const BIGNUM *a,
    233                                 const BIGNUM *b, BN_CTX *);
    234 void ec_GFp_mont_group_finish(EC_GROUP *);
    235 void ec_GFp_mont_group_clear_finish(EC_GROUP *);
    236 int ec_GFp_mont_group_copy(EC_GROUP *, const EC_GROUP *);
    237 int ec_GFp_mont_field_mul(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
    238                           const BIGNUM *b, BN_CTX *);
    239 int ec_GFp_mont_field_sqr(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
    240                           BN_CTX *);
    241 int ec_GFp_mont_field_encode(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
    242                              BN_CTX *);
    243 int ec_GFp_mont_field_decode(const EC_GROUP *, BIGNUM *r, const BIGNUM *a,
    244                              BN_CTX *);
    245 int ec_GFp_mont_field_set_to_one(const EC_GROUP *, BIGNUM *r, BN_CTX *);
    246 
    247 int ec_point_set_Jprojective_coordinates_GFp(const EC_GROUP *group,
    248                                              EC_POINT *point, const BIGNUM *x,
    249                                              const BIGNUM *y, const BIGNUM *z,
    250                                              BN_CTX *ctx);
    251 
    252 void ec_GFp_nistp_points_make_affine_internal(
    253     size_t num, void *point_array, size_t felem_size, void *tmp_felems,
    254     void (*felem_one)(void *out), int (*felem_is_zero)(const void *in),
    255     void (*felem_assign)(void *out, const void *in),
    256     void (*felem_square)(void *out, const void *in),
    257     void (*felem_mul)(void *out, const void *in1, const void *in2),
    258     void (*felem_inv)(void *out, const void *in),
    259     void (*felem_contract)(void *out, const void *in));
    260 
    261 void ec_GFp_nistp_recode_scalar_bits(uint8_t *sign, uint8_t *digit, uint8_t in);
    262 
    263 const EC_METHOD *EC_GFp_nistp224_method(void);
    264 const EC_METHOD *EC_GFp_nistp256_method(void);
    265 
    266 /* Returns GFp methods using montgomery multiplication, with x86-64
    267  * optimized P256. See http://eprint.iacr.org/2013/816. */
    268 const EC_METHOD *EC_GFp_nistz256_method(void);
    269 
    270 struct ec_key_st {
    271   int version;
    272 
    273   EC_GROUP *group;
    274 
    275   EC_POINT *pub_key;
    276   BIGNUM *priv_key;
    277 
    278   unsigned int enc_flag;
    279   point_conversion_form_t conv_form;
    280 
    281   CRYPTO_refcount_t references;
    282   int flags;
    283 
    284   ECDSA_METHOD *ecdsa_meth;
    285 
    286   CRYPTO_EX_DATA ex_data;
    287 } /* EC_KEY */;
    288 
    289 /* curve_data contains data about a built-in elliptic curve. */
    290 struct curve_data {
    291   /* comment is a human-readable string describing the curve. */
    292   const char *comment;
    293   /* param_len is the number of bytes needed to store a field element. */
    294   uint8_t param_len;
    295   /* cofactor is the cofactor of the group (i.e. the number of elements in the
    296    * group divided by the size of the main subgroup. */
    297   uint8_t cofactor; /* promoted to BN_ULONG */
    298   /* data points to an array of 6*|param_len| bytes which hold the field
    299    * elements of the following (in big-endian order): prime, a, b, generator x,
    300    * generator y, order. */
    301   const uint8_t data[];
    302 };
    303 
    304 struct built_in_curve {
    305   int nid;
    306   const struct curve_data *data;
    307   const EC_METHOD *(*method)(void);
    308 };
    309 
    310 /* OPENSSL_built_in_curves is terminated with an entry where |nid| is
    311  * |NID_undef|. */
    312 extern const struct built_in_curve OPENSSL_built_in_curves[];
    313 
    314 #if defined(__cplusplus)
    315 }  /* extern C */
    316 #endif
    317 
    318 #endif  /* OPENSSL_HEADER_EC_INTERNAL_H */
    319