text: /* ecc.h
   *
   * Copyright (C) 2006-2015 wolfSSL Inc.
   *
   * This file is part of wolfSSL. (formerly known as CyaSSL)
   *
   * wolfSSL 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.
   *
   * wolfSSL 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 WOLF_CRYPT_ECC_H
  #define WOLF_CRYPT_ECC_H
  
  #include <wolfssl/wolfcrypt/types.h>
  
  #ifdef HAVE_ECC
  
  #include <wolfssl/wolfcrypt/integer.h>
  #include <wolfssl/wolfcrypt/random.h>
  
  #ifdef __cplusplus
      extern "C" {
  #endif
  
  enum {
      ECC_PUBLICKEY  = 1,
      ECC_PRIVATEKEY = 2,
      ECC_MAXNAME    = 16,     /* MAX CURVE NAME LENGTH */
      SIG_HEADER_SZ  =  6,     /* ECC signature header size */
      ECC_BUFSIZE    = 256,    /* for exported keys temp buffer */
      ECC_MINSIZE    = 20,     /* MIN Private Key size */
      ECC_MAXSIZE    = 66      /* MAX Private Key size */
  };
  
  
  /* ECC set type defined a NIST GF(p) curve */
  typedef struct {
      int size;       /* The size of the curve in octets */
      const char* name;     /* name of this curve */
      const char* prime;    /* prime that defines the field, curve is in (hex) */
      const char* Af;       /* fields A param (hex) */
      const char* Bf;       /* fields B param (hex) */
      const char* order;    /* order of the curve (hex) */
      const char* Gx;       /* x coordinate of the base point on curve (hex) */
      const char* Gy;       /* y coordinate of the base point on curve (hex) */
  } ecc_set_type;
  
  
  #ifdef ALT_ECC_SIZE
  
  /* Note on ALT_ECC_SIZE:
   * The fast math code uses an array of a fixed size to store the big integers.
   * By default, the array is big enough for RSA keys. There is a size,
   * FP_MAX_BITS which can be used to make the array smaller when one wants ECC
   * but not RSA. Some people want fast math sized for both RSA and ECC, where
   * ECC won't use as much as RSA. The flag ALT_ECC_SIZE switches in an alternate
   * ecc_point structure that uses an alternate fp_int that has a shorter array
   * of fp_digits.
   *
   * Now, without ALT_ECC_SIZE, the ecc_point has three single item arrays of
   * mp_ints for the components of the point. With ALT_ECC_SIZE, the components
   * of the point are pointers that are set to each of a three item array of
   * alt_fp_ints. While an mp_int will have 4096 bits of digit inside the
   * structure, the alt_fp_int will only have 512 bits. A size value was added
   * in the ALT case, as well, and is set by mp_init() and alt_fp_init(). The
   * functions fp_zero() and fp_copy() use the size parameter. An int needs to
   * be initialized before using it instead of just fp_zeroing it, the init will
   * call zero. FP_MAX_BITS_ECC defaults to 512, but can be set to change the
   * number of bits used in the alternate FP_INT.
   *
   * Do not enable ALT_ECC_SIZE and disable fast math in the configuration.
   */
  
  #ifndef FP_MAX_BITS_ECC
      #define FP_MAX_BITS_ECC           512
  #endif
  #define FP_MAX_SIZE_ECC           (FP_MAX_BITS_ECC+(8*DIGIT_BIT))
  #if FP_MAX_BITS_ECC % CHAR_BIT
     #error FP_MAX_BITS_ECC must be a multiple of CHAR_BIT
  #endif
  #define FP_SIZE_ECC    (FP_MAX_SIZE_ECC/DIGIT_BIT)
  
  /* This needs to match the size of the fp_int struct, except the
   * fp_digit array will be shorter. */
  typedef struct alt_fp_int {
      int used, sign, size;
      fp_digit dp[FP_SIZE_ECC];
  } alt_fp_int;
  #endif
  
  /* A point on an ECC curve, stored in Jacbobian format such that (x,y,z) =>
     (x/z^2, y/z^3, 1) when interpreted as affine */
  typedef struct {
  #ifndef ALT_ECC_SIZE
      mp_int x[1];        /* The x coordinate */
      mp_int y[1];        /* The y coordinate */
      mp_int z[1];        /* The z coordinate */
  #else
      mp_int* x;        /* The x coordinate */
      mp_int* y;        /* The y coordinate */
      mp_int* z;        /* The z coordinate */
      alt_fp_int xyz[3];
  #endif
  } ecc_point;
  
  
  /* An ECC Key */
  typedef struct {
      int type;           /* Public or Private */
      int idx;            /* Index into the ecc_sets[] for the parameters of
                             this curve if -1, this key is using user supplied
                             curve in dp */
      const ecc_set_type* dp;     /* domain parameters, either points to NIST
                                     curves (idx >= 0) or user supplied */
      ecc_point pubkey;   /* public key */
      mp_int    k;        /* private key */
  } ecc_key;
  
  
  /* ECC predefined curve sets  */
  extern const ecc_set_type ecc_sets[];
  
  
  WOLFSSL_API
  int wc_ecc_make_key(RNG* rng, int keysize, ecc_key* key);
  WOLFSSL_API
  int wc_ecc_check_key(ecc_key* key);
  WOLFSSL_API
  int wc_ecc_shared_secret(ecc_key* private_key, ecc_key* public_key, byte* out,
                        word32* outlen);
  WOLFSSL_API
  int wc_ecc_sign_hash(const byte* in, word32 inlen, byte* out, word32 *outlen, 
                    RNG* rng, ecc_key* key);
  WOLFSSL_API
  int wc_ecc_verify_hash(const byte* sig, word32 siglen, const byte* hash,
                      word32 hashlen, int* stat, ecc_key* key);
  WOLFSSL_API
  int wc_ecc_init(ecc_key* key);
  WOLFSSL_API
  void wc_ecc_free(ecc_key* key);
  WOLFSSL_API
  void wc_ecc_fp_free(void);
  
  
  /* ASN key helpers */
  WOLFSSL_API
  int wc_ecc_export_x963(ecc_key*, byte* out, word32* outLen);
  WOLFSSL_API
  int wc_ecc_export_x963_ex(ecc_key*, byte* out, word32* outLen, int compressed);
      /* extended functionality with compressed option */
  WOLFSSL_API
  int wc_ecc_import_x963(const byte* in, word32 inLen, ecc_key* key);
  WOLFSSL_API
  int wc_ecc_import_private_key(const byte* priv, word32 privSz, const byte* pub,
                             word32 pubSz, ecc_key* key);
  WOLFSSL_API
  int wc_ecc_rs_to_sig(const char* r, const char* s, byte* out, word32* outlen);
  WOLFSSL_API
  int wc_ecc_import_raw(ecc_key* key, const char* qx, const char* qy,
                     const char* d, const char* curveName);
  
  WOLFSSL_API
  int wc_ecc_export_private_only(ecc_key* key, byte* out, word32* outLen);
  
  /* size helper */
  WOLFSSL_API
  int wc_ecc_size(ecc_key* key);
  WOLFSSL_API
  int wc_ecc_sig_size(ecc_key* key);
  
  
  #ifdef HAVE_ECC_ENCRYPT
  /* ecc encrypt */
  
  enum ecEncAlgo {
      ecAES_128_CBC = 1,  /* default */
      ecAES_256_CBC = 2
  };
  
  enum ecKdfAlgo {
      ecHKDF_SHA256 = 1,  /* default */
      ecHKDF_SHA1   = 2
  };
  
  enum ecMacAlgo {
      ecHMAC_SHA256 = 1,  /* default */
      ecHMAC_SHA1   = 2
  };
  
  enum {
      KEY_SIZE_128     = 16,
      KEY_SIZE_256     = 32,
      IV_SIZE_64       =  8,
      EXCHANGE_SALT_SZ = 16,
      EXCHANGE_INFO_SZ = 23
  };
  
  enum ecFlags {
      REQ_RESP_CLIENT = 1,
      REQ_RESP_SERVER = 2
  };
  
  
  typedef struct ecEncCtx ecEncCtx;
  
  WOLFSSL_API
  ecEncCtx* wc_ecc_ctx_new(int flags, RNG* rng);
  WOLFSSL_API
  void wc_ecc_ctx_free(ecEncCtx*);
  WOLFSSL_API
  int wc_ecc_ctx_reset(ecEncCtx*, RNG*);   /* reset for use again w/o alloc/free */
  
  WOLFSSL_API
  const byte* wc_ecc_ctx_get_own_salt(ecEncCtx*);
  WOLFSSL_API
  int wc_ecc_ctx_set_peer_salt(ecEncCtx*, const byte* salt);
  WOLFSSL_API
  int wc_ecc_ctx_set_info(ecEncCtx*, const byte* info, int sz);
  
  WOLFSSL_API
  int wc_ecc_encrypt(ecc_key* privKey, ecc_key* pubKey, const byte* msg,
                  word32 msgSz, byte* out, word32* outSz, ecEncCtx* ctx);
  WOLFSSL_API
  int wc_ecc_decrypt(ecc_key* privKey, ecc_key* pubKey, const byte* msg,
                  word32 msgSz, byte* out, word32* outSz, ecEncCtx* ctx);
  
  #endif /* HAVE_ECC_ENCRYPT */
  
  #ifdef __cplusplus
      }    /* extern "C" */
  #endif
  
  #endif /* HAVE_ECC */
  #endif /* WOLF_CRYPT_ECC_H */
  