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/* Copyright (C) 2001 Artifex Software, Inc. All rights reserved.
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This software is provided AS-IS with no warranty, either express or
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implied.
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This software is distributed under license and may not be copied,
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modified or distributed except as expressly authorized under the terms
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of the license contained in the file LICENSE in this distribution.
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For more information about licensing, please refer to
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http://www.ghostscript.com/licensing/. For information on
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commercial licensing, go to http://www.artifex.com/licensing/ or
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contact Artifex Software, Inc., 101 Lucas Valley Road #110,
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San Rafael, CA 94903, U.S.A., +1(415)492-9861.
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*/
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/* $Id: zfarc4.c,v 1.4 2002/02/21 22:24:54 giles Exp $ */
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/* this is the ps interpreter interface to the arcfour cipher filter
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used in PDF encryption. We provide both Decode and Encode filters;
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the cipher is symmetric, so the call to the underlying routines is
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identical between the two filters */
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#include "memory_.h"
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#include "ghost.h"
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#include "oper.h"
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#include "gsstruct.h"
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#include "ialloc.h"
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#include "idict.h"
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#include "stream.h"
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#include "strimpl.h"
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#include "ifilter.h"
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#include "sarc4.h"
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/* <source> <dict> arcfour/filter <file> */
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private int
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z_arcfour_d(i_ctx_t * i_ctx_p)
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{
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os_ptr op = osp; /* i_ctx_p->op_stack.stack.p defined in osstack.h */
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ref *sop = NULL;
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stream_arcfour_state state;
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/* extract the key from the parameter dictionary */
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check_type(*op, t_dictionary);
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check_dict_read(*op);
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if (dict_find_string(op, "Key", &sop) <= 0)
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return_error(e_rangecheck);
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s_arcfour_set_key(&state, sop->value.const_bytes, r_size(sop));
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/* we pass npop=0, since we've no arguments left to consume */
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/* we pass 0 instead of the usual rspace(sop) will allocate storage for
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filter state from the same memory pool as the stream it's coding. this
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causes no trouble because we maintain no pointers */
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return filter_read(i_ctx_p, 0, &s_arcfour_template,
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(stream_state *) & state, 0);
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}
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/* encode version of the filter */
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private int
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z_arcfour_e(i_ctx_t * i_ctx_p)
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{
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os_ptr op = osp; /* i_ctx_p->op_stack.stack.p defined in osstack.h */
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ref *sop = NULL;
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stream_arcfour_state state;
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/* extract the key from the parameter dictionary */
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check_type(*op, t_dictionary);
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check_dict_read(*op);
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if (dict_find_string(op, "Key", &sop) <= 0)
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return_error(e_rangecheck);
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s_arcfour_set_key(&state, sop->value.const_bytes, r_size(sop));
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/* we pass npop=0, since we've no arguments left to consume */
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/* we pass 0 instead of the usual rspace(sop) will allocate storage for
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filter state from the same memory pool as the stream it's coding. this
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causes no trouble because we maintain no pointers */
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return filter_write(i_ctx_p, 0, &s_arcfour_template,
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(stream_state *) & state, 0);
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}
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/* match the above routines to their postscript filter names
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this is how our 'private' routines get called externally */
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const op_def zfarc4_op_defs[] = {
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op_def_begin_filter(),
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{"2ArcfourDecode", z_arcfour_d},
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{"2ArcfourEncode", z_arcfour_e},
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op_def_end(0)
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};
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