/* ecc.h
 *
 * Copyright (C) 2006-2014 wolfSSL Inc.
 *
 * This file is part of CyaSSL.
 *
 * CyaSSL 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.
 *
 * CyaSSL 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
 */

#ifdef HAVE_ECC

#ifndef CTAO_CRYPT_ECC_H
#define CTAO_CRYPT_ECC_H

#include <cyassl/ctaocrypt/types.h>
#include <cyassl/ctaocrypt/integer.h>
#include <cyassl/ctaocrypt/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;


/* 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 {
    mp_int x;        /* The x coordinate */
    mp_int y;        /* The y coordinate */
    mp_int z;        /* The z coordinate */
} 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[];


CYASSL_API
int ecc_make_key(RNG* rng, int keysize, ecc_key* key);
CYASSL_API
int ecc_shared_secret(ecc_key* private_key, ecc_key* public_key, byte* out,
                      word32* outlen);
CYASSL_API
int ecc_sign_hash(const byte* in, word32 inlen, byte* out, word32 *outlen, 
                  RNG* rng, ecc_key* key);
CYASSL_API
int ecc_verify_hash(const byte* sig, word32 siglen, const byte* hash,
                    word32 hashlen, int* stat, ecc_key* key);
CYASSL_API
void ecc_init(ecc_key* key);
CYASSL_API
void ecc_free(ecc_key* key);
CYASSL_API
void ecc_fp_free(void);


/* ASN key helpers */
CYASSL_API
int ecc_export_x963(ecc_key*, byte* out, word32* outLen);
CYASSL_API
int ecc_export_x963_ex(ecc_key*, byte* out, word32* outLen, int compressed);
    /* extended functionality with compressed option */
CYASSL_API
int ecc_import_x963(const byte* in, word32 inLen, ecc_key* key);
CYASSL_API
int ecc_import_private_key(const byte* priv, word32 privSz, const byte* pub,
                           word32 pubSz, ecc_key* key);
CYASSL_API
int ecc_rs_to_sig(const char* r, const char* s, byte* out, word32* outlen);
CYASSL_API
int ecc_import_raw(ecc_key* key, const char* qx, const char* qy,
                   const char* d, const char* curveName);

CYASSL_API
int ecc_export_private_only(ecc_key* key, byte* out, word32* outLen);

/* size helper */
CYASSL_API
int ecc_size(ecc_key* key);
CYASSL_API
int 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;

CYASSL_API
ecEncCtx* ecc_ctx_new(int flags, RNG* rng);
CYASSL_API
void ecc_ctx_free(ecEncCtx*);
CYASSL_API
int ecc_ctx_reset(ecEncCtx*, RNG*);   /* reset for use again w/o alloc/free */

CYASSL_API
const byte* ecc_ctx_get_own_salt(ecEncCtx*);
CYASSL_API
int ecc_ctx_set_peer_salt(ecEncCtx*, const byte* salt);
CYASSL_API
int ecc_ctx_set_info(ecEncCtx*, const byte* info, int sz);

CYASSL_API
int ecc_encrypt(ecc_key* privKey, ecc_key* pubKey, const byte* msg,
                word32 msgSz, byte* out, word32* outSz, ecEncCtx* ctx);
CYASSL_API
int 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 /* CTAO_CRYPT_ECC_H */
#endif /* HAVE_ECC */
