gnupg/common/openpgp-s2k.c

68 lines
1.8 KiB
C

/* openpgp-s2ks.c - OpenPGP S2K helper functions
* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004,
* 2005, 2006 Free Software Foundation, Inc.
* Copyright (C) 2010, 2019 g10 Code GmbH
*
* This file is part of GnuPG.
*
* This file is free software; you can redistribute it and/or modify
* it under the terms of either
*
* - the GNU Lesser General Public License as published by the Free
* Software Foundation; either version 3 of the License, or (at
* your option) any later version.
*
* or
*
* - 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.
*
* or both in parallel, as here.
*
* This file 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, see <https://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <stdlib.h>
#include <errno.h>
#include <ctype.h>
#include <assert.h>
#include "util.h"
#include "openpgpdefs.h"
/* Pack an s2k iteration count into the form specified in RFC-4880.
* If we're in between valid values, round up. */
unsigned char
encode_s2k_iterations (int iterations)
{
unsigned char c=0;
unsigned char result;
unsigned int count;
if (iterations <= 1024)
return 0; /* Command line arg compatibility. */
if (iterations >= 65011712)
return 255;
/* Need count to be in the range 16-31 */
for (count=iterations>>6; count>=32; count>>=1)
c++;
result = (c<<4)|(count-16);
if (S2K_DECODE_COUNT(result) < iterations)
result++;
return result;
}