/**
 *
 * <rng.h>
 *
 * @version 2.0 (March 2019)
 *
 * Reference ISO-C11 Implementation of the LEDAcrypt KEM-LT cipher using GCC built-ins.
 *
 * In alphabetical order:
 *
 * @author Marco Baldi <m.baldi@univpm.it>
 * @author Alessandro Barenghi <alessandro.barenghi@polimi.it>
 * @author Franco Chiaraluce <f.chiaraluce@univpm.it>
 * @author Gerardo Pelosi <gerardo.pelosi@polimi.it>
 * @author Paolo Santini <p.santini@pm.univpm.it>
 *
 * This code is hereby placed in the public domain.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ''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 THE AUTHORS OR CONTRIBUTORS 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.
 *
 **/

#pragma once

/******  From this point on, the code was supplied by NIST ****************/
//  Created by Bassham, Lawrence E (Fed) on 8/29/17.
//  Copyright © 2017 Bassham, Lawrence E (Fed). All rights reserved.
//
/******    from NIST  ****************/

#include <stdio.h>

#define RNG_SUCCESS      0
#define RNG_BAD_MAXLEN  -1
#define RNG_BAD_OUTBUF  -2
#define RNG_BAD_REQ_LEN -3

typedef struct {
    unsigned char   buffer[16];
    int             buffer_pos;
    unsigned long   length_remaining;
    unsigned char   key[32];
    unsigned char   ctr[16];
} AES_XOF_struct;

typedef struct {
    unsigned char   Key[32];
    unsigned char   V[16];
    int             reseed_counter;
} AES256_CTR_DRBG_struct;


void
AES256_CTR_DRBG_Update(unsigned char *provided_data,
                       unsigned char *Key,
                       unsigned char *V);

int
seedexpander_init(AES_XOF_struct *ctx,
                  unsigned char *seed,
                  unsigned char *diversifier,
                  unsigned long maxlen);

int
seedexpander(AES_XOF_struct *ctx, unsigned char *x, unsigned long xlen);

void
randombytes_init(unsigned char *entropy_input,
                 unsigned char *personalization_string,
                 int security_strength);

int
randombytes(unsigned char *x, unsigned long long xlen);

/******  End of NIST supplied code ****************/

void initialize_pseudo_random_generator_seed(int ac, char *av[]);

void deterministic_random_byte_generator(unsigned char *const output,
        const unsigned long long output_len,
        const unsigned char *const seed,
        const unsigned long long seed_length);

void seedexpander_from_trng(AES_XOF_struct *ctx,
                            const unsigned char *trng_entropy
                            /* TRNG_BYTE_LENGTH wide buffer */);