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+% Copyright (C) 1992, 1993 Aladdin Enterprises. All rights reserved.
+%
+% This software is provided AS-IS with no warranty, either express or
+% implied.
+%
+% This software is distributed under license and may not be copied,
+% modified or distributed except as expressly authorized under the terms
+% of the license contained in the file LICENSE in this distribution.
+%
+% For more information about licensing, please refer to
+% http://www.ghostscript.com/licensing/. For information on
+% commercial licensing, go to http://www.artifex.com/licensing/ or
+% contact Artifex Software, Inc., 101 Lucas Valley Road #110,
+% San Rafael, CA 94903, U.S.A., +1(415)492-9861.
+
+% $Id: type1enc.ps 6300 2005-12-28 19:56:24Z giles $
+% type1enc.ps
+% PostScript language versions of the Type 1 encryption/decryption algorithms.
+
+% This file is normally not needed with Ghostscript, since Ghostscript
+% implements these algorithms in C. For the specifications, see Chapter 7 of
+% "Adobe Type 1 Font Format," ISBN 0-201-57044-0, published by Addison-Wesley.
+
+/.type1crypt % <R> <from> <to> <proc> .type1crypt <R'> <to>
+ % (auxiliary procedure)
+ { 4 1 roll
+ 0 2 index length getinterval
+ 0 1 2 index length 1 sub
+ { % Stack: proc R from to index
+ 2 index 1 index get % proc R from to index C/P
+ 4 index -8 bitshift xor 3 copy put % proc R from to index P/C
+ 5 index exec % proc R from to C
+
+% Compute R' = ((R + C) * 52845 + 22719) mod 65536
+% without exceeding a 31-bit integer magnitude, given that
+% 0 <= R <= 65535 and 0 <= C <= 255.
+
+ 4 -1 roll add
+ dup 20077 mul % 52845 - 32768
+ exch 1 and 15 bitshift add % only care about 16 low-order bits
+ 22719 add 65535 and 3 1 roll
+ }
+ for exch pop 3 -1 roll pop
+ } bind def
+
+% <state> <fromString> <toString> .type1encrypt <newState> <toSubstring>
+% Encrypts fromString according to the algorithm for Adobe
+% Type 1 fonts, writing the result into toString.
+% toString must be at least as long as fromString or a
+% rangecheck error occurs. state is the initial state of
+% the encryption algorithm (a 16-bit non-negative
+% integer); newState is the new state of the algorithm.
+
+/.type1encrypt
+ { { exch pop } .type1crypt
+ } bind def
+
+% <state> <fromString> <toString> .type1decrypt <newState> <toSubstring>
+% Decrypts fromString according to the algorithm for Adobe
+% Type 1 fonts, writing the result into toString. Other
+% specifications are as for type1encrypt.
+
+/.type1decrypt
+ { { pop 2 index exch get } .type1crypt
+ } bind def