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99 lines
2.7 KiB
C
99 lines
2.7 KiB
C
/*
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This file is part of Pretty Curved Privacy (pcp1).
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Copyright (C) 2013 T.Linden.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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You can contact me by mail: <tlinden AT cpan DOT org>.
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*/
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#ifndef _HAVE_PCP_ZPADDING
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#define _HAVE_PCP_ZPADDING
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <stdlib.h>
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#include <limits.h>
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#include "mem.h"
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#ifdef DEBUG
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#define ZPADCHAR 48
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#else
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#define ZPADCHAR 0
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#endif
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// prepends a binary stream with a number of
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// \0's as required by the secret_box and
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// secret_box_open functions of libsodium.
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//
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// parameters:
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//
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// padded: destination array (ref)
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// unpadded: source array without padding
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// padlen: length of padding
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// unpadlen: length of source array
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//
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// turns "efa5" into "00000000efa5" with padlen 8
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//
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// if DEBUG is set, destination will be padded with
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// the character '0', NOT the integer 0.
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//
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// allocates memory for padded and it is up to the
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// user to free it after use.
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//
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// sample call:
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//
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// char unpadded[] = {0xef, 0xa5};
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// unsigned char *padded;
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// pcp_pad_prepend(&padded, unpadded, 8, 2);
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//
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// the result, padded, would be 10 bytes long, 8
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// bytes for the leading zeros and 2 for the content
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// of the original unpadded.
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void pcp_pad_prepend(unsigned char **padded, unsigned char *unpadded,
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size_t padlen, size_t unpadlen);
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// removes zero's of a binary stream, which is
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// the reverse of pcp_pad_prepend().
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//
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// parameters:
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//
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// unpadded: destination array (ref), with padding removed
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// padded: source array with padding
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// padlen: length of padding
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// unpadlen: length of source array
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//
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// turns "00000000efa5" into "efa5" with padlen 8
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//
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// allocates memory for unpadded and it is up to the
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// user to free it after use.
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//
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// sample call:
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//
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// char padded[] = {0x0, 0x0, 0x0, 0x0, 0xef, 0xa5};
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// unsigned char *unpadded;
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// pcp_pad_remove(unpadded, padded, 4, 2);
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//
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// the result, unpadded would be 2 bytes long containing
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// only the 2 bytes we want to have with zeros removed.
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void pcp_pad_remove(unsigned char **unpadded, unsigned char *padded,
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size_t padlen, size_t unpadlen);
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#endif // _HAVE_PCP_ZPADDING
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