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src/src/lib/scryptenc/scryptenc.c  view on Meta::CPAN

/*-
 * Copyright 2009 Colin Percival
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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 BY THE AUTHOR AND CONTRIBUTORS ``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 AUTHOR 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.
 *
 * This file was originally written by Colin Percival as part of the Tarsnap
 * online backup system.
 */
#include "scrypt_platform.h"

#include <errno.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include <openssl/aes.h>

#include "crypto_aesctr.h"
#include "crypto_scrypt.h"
#include "memlimit.h"
#include "scryptenc_cpuperf.h"
#include "sha256.h"
#include "sysendian.h"

#include "scryptenc.h"

#define ENCBLOCK 65536

static int pickparams(size_t, double, double,
    int *, uint32_t *, uint32_t *);
static int checkparams(size_t, double, double, int, uint32_t, uint32_t);
static int getsalt(uint8_t[32]);

static int
pickparams(size_t maxmem, double maxmemfrac, double maxtime,
    int * logN, uint32_t * r, uint32_t * p)
{
	size_t memlimit;
	double opps;
	double opslimit;
	double maxN, maxrp;
	int rc;

	/* Figure out how much memory to use. */
	if (memtouse(maxmem, maxmemfrac, &memlimit))
		return (1);

	/* Figure out how fast the CPU is. */
	if ((rc = scryptenc_cpuperf(&opps)) != 0)
		return (rc);
	opslimit = opps * maxtime;

	/* Allow a minimum of 2^15 salsa20/8 cores. */
	if (opslimit < 32768)
		opslimit = 32768;

	/* Fix r = 8 for now. */
	*r = 8;

	/*
	 * The memory limit requires that 128Nr <= memlimit, while the CPU
	 * limit requires that 4Nrp <= opslimit.  If opslimit < memlimit/32,
	 * opslimit imposes the stronger limit on N.
	 */
#ifdef DEBUG