/* Copyright (c) 2015, Vsevolod Stakhov
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *       * Redistributions of source code must retain the above copyright
 *         notice, this list of conditions and the following disclaimer.
 *       * Redistributions in binary form must reproduce the above copyright
 *         notice, this list of conditions and the following disclaimer in the
 *         documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL AUTHOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#ifndef CRYPTOBOX_H_
#define CRYPTOBOX_H_

#include "config.h"

#define rspamd_cryptobox_NONCEBYTES 24
#define rspamd_cryptobox_PKBYTES 32
#define rspamd_cryptobox_SKBYTES 32
#define rspamd_cryptobox_MACBYTES 16
#define rspamd_cryptobox_NMBYTES 32

typedef guchar rspamd_pk_t[rspamd_cryptobox_PKBYTES];
typedef guchar rspamd_sk_t[rspamd_cryptobox_SKBYTES];
typedef guchar rspamd_sig_t[rspamd_cryptobox_MACBYTES];
typedef guchar rspamd_nm_t[rspamd_cryptobox_NMBYTES];
typedef guchar rspamd_nonce_t[rspamd_cryptobox_NONCEBYTES];

/**
 * Init cryptobox library
 */
void rspamd_cryptobox_init (void);

/**
 * Generate new keypair
 * @param pk public key buffer
 * @param sk secret key buffer
 */
void rspamd_cryptobox_keypair (rspamd_pk_t pk, rspamd_sk_t sk);

/**
 * Encrypt segments of data inplace adding signature to sig afterwards
 * @param segments segments of data
 * @param cnt count of segments
 * @param pk remote pubkey
 * @param sk local secret key
 * @param sig output signature
 */
void rspamd_cryptobox_encrypt_inplace (guchar *data, gsize len,
		const rspamd_nonce_t nonce,
		const rspamd_pk_t pk, const rspamd_sk_t sk, rspamd_sig_t sig);


/**
 * Decrypt and verify data chunk inplace
 * @param data data to decrypt
 * @param len lenght of data
 * @param pk remote pubkey
 * @param sk local privkey
 * @param sig signature input
 * @return TRUE if input has been verified successfully
 */
gboolean rspamd_cryptobox_decrypt_inplace (guchar *data, gsize len,
		const rspamd_nonce_t nonce,
		const rspamd_pk_t pk, const rspamd_sk_t sk, const rspamd_sig_t sig);

/**
 * Encrypt segments of data inplace adding signature to sig afterwards
 * @param segments segments of data
 * @param cnt count of segments
 * @param pk remote pubkey
 * @param sk local secret key
 * @param sig output signature
 */
void rspamd_cryptobox_encrypt_nm_inplace (guchar *data, gsize len,
		const rspamd_nonce_t nonce,
		const rspamd_nm_t nm, rspamd_sig_t sig);


/**
 * Decrypt and verify data chunk inplace
 * @param data data to decrypt
 * @param len lenght of data
 * @param pk remote pubkey
 * @param sk local privkey
 * @param sig signature input
 * @return TRUE if input has been verified successfully
 */
gboolean rspamd_cryptobox_decrypt_nm_inplace (guchar *data, gsize len,
		 const rspamd_nonce_t nonce,
		 const rspamd_nm_t nm, const rspamd_sig_t sig);

/**
 * Generate shared secret from local sk and remote pk
 * @param nm shared secret
 * @param pk remote pubkey
 * @param sk local privkey
 */
void rspamd_cryptobox_nm (rspamd_nm_t nm, const rspamd_pk_t pk, const rspamd_sk_t sk);

/**
 * Securely clear the buffer specified
 * @param buf buffer to zero
 * @param buflen length of buffer
 */
void rspamd_explicit_memzero (void * const buf, gsize buflen);

#endif /* CRYPTOBOX_H_ */