/* chacha.h
 *
 * Copyright (C) 2006-2017 wolfSSL Inc.
 *
 * This file is part of wolfSSL.
 *
 * 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 02110-1335, USA
 */


#ifndef WOLF_CRYPT_CHACHA_H
# define WOLF_CRYPT_CHACHA_H

# include <wolfssl/wolfcrypt/types.h>

# ifdef HAVE_CHACHA

#  ifdef __cplusplus
extern "C" {
#  endif

/* Size of the IV */
#  define CHACHA_IV_WORDS 3
#  define CHACHA_IV_BYTES (CHACHA_IV_WORDS * sizeof(word32))

/* Size of ChaCha chunks */
#  define CHACHA_CHUNK_WORDS 16
#  define CHACHA_CHUNK_BYTES (CHACHA_CHUNK_WORDS * sizeof(word32))

enum {
    CHACHA_ENC_TYPE = 7 /* cipher unique type */
};

typedef struct ChaCha {
    word32 X[CHACHA_CHUNK_WORDS]; /* state of cipher */
} ChaCha;

/**
 * IV(nonce) changes with each record
 * counter is for what value the block counter should start ... usually 0
 */
WOLFSSL_API int
wc_Chacha_SetIV(ChaCha * ctx, const byte * inIv, word32 counter);

WOLFSSL_API int
wc_Chacha_Process(ChaCha * ctx, byte * cipher, const byte * plain,
  word32 msglen);
WOLFSSL_API int
wc_Chacha_SetKey(ChaCha * ctx, const byte * key, word32 keySz);

#  ifdef __cplusplus
} /* extern "C" */
#  endif

# endif /* HAVE_CHACHA */
#endif  /* WOLF_CRYPT_CHACHA_H */
