1 /* Copyright (C) 1990, 1992, 1997 Aladdin Enterprises. All rights reserved. 2 3 This software is provided AS-IS with no warranty, either express or 4 implied. 5 6 This software is distributed under license and may not be copied, 7 modified or distributed except as expressly authorized under the terms 8 of the license contained in the file LICENSE in this distribution. 9 10 For more information about licensing, please refer to 11 http://www.ghostscript.com/licensing/. For information on 12 commercial licensing, go to http://www.artifex.com/licensing/ or 13 contact Artifex Software, Inc., 101 Lucas Valley Road #110, 14 San Rafael, CA 94903, U.S.A., +1(415)492-9861. 15 */ 16 17 /* $Id: gscrypt1.h,v 1.5 2002/06/16 08:45:42 lpd Exp $ */ 18 /* Interface to Adobe Type 1 encryption/decryption. */ 19 20 #ifndef gscrypt1_INCLUDED 21 # define gscrypt1_INCLUDED 22 23 /* Normal public interface */ 24 typedef ushort crypt_state; 25 int gs_type1_encrypt(byte * dest, const byte * src, uint len, 26 crypt_state * pstate); 27 int gs_type1_decrypt(byte * dest, const byte * src, uint len, 28 crypt_state * pstate); 29 30 /* Define the encryption parameters and procedures. */ 31 #define crypt_c1 ((ushort)52845) 32 #define crypt_c2 ((ushort)22719) 33 /* c1 * c1' == 1 mod 2^16. */ 34 #define crypt_c1_inverse ((ushort)27493) 35 #define encrypt_next(ch, state, chvar)\ 36 (chvar = ((ch) ^ (state >> 8)),\ 37 state = (chvar + state) * crypt_c1 + crypt_c2) 38 #define decrypt_this(ch, state)\ 39 ((ch) ^ (state >> 8)) 40 #define decrypt_next(ch, state, chvar)\ 41 (chvar = decrypt_this(ch, state),\ 42 decrypt_skip_next(ch, state)) 43 #define decrypt_skip_next(ch, state)\ 44 (state = ((ch) + state) * crypt_c1 + crypt_c2) 45 #define decrypt_skip_previous(ch, state)\ 46 (state = (state - crypt_c2) * crypt_c1_inverse - (ch)) 47 48 #endif /* gscrypt1_INCLUDED */ 49