% Copyright (C) 1992, 1993 Aladdin Enterprises. All rights reserved. % % This program is free software; you can redistribute it and/or modify it % under the terms of 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. % % This program 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, write to the Free Software Foundation, Inc., % 59 Temple Place, Suite 330, Boston, MA, 02111-1307. % $Id: type1enc.ps,v 1.2.6.1.2.1 2003/04/12 14:02:39 giles Exp $ % 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 % .type1crypt % (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 % .type1encrypt % 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 % .type1decrypt % 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