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diff --git a/engines/glk/archetype/crypt.h b/engines/glk/archetype/crypt.h
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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#ifndef ARCHETYPE_CRYPT
+#define ARCHETYPE_CRYPT
+
+#include "common/scummsys.h"
+#include "common/str.h"
+
+namespace Glk {
+namespace Archetype {
+
+enum EncryptionType {
+	NONE, SIMPLE, PURPLE, UNPURPLE, COMPLEX, DEBUGGING_ON
+};
+
+extern byte CryptMask;
+extern EncryptionType Encryption;
+
+/**
+ * Initializes fields local to the file
+ */
+extern void crypt_init();
+
+extern void cryptinit(EncryptionType crypt_kind, uint seed);
+
+/**
+ * Encrypts or decrypts a string.Since all encryption methods are based on XOR,
+ * the same method both encrypts anddecrypts.
+ * If <method> is SIMPLE, the CryptMask is simply XORed with each byte in the string.
+ * If <method> is PURPLE, the CryptMask is changed each time after using it,
+ * by adding to it the lowest three bits of the result of the last encrypted
+ * byte.This way the mask changes frequently anddynamically in a way that
+ * is difficult to predict.
+ * If <method> is UNPURPLE, the same algorithm as PURPLE is used except that
+ * the next CryptMask must be determined before altering the byte under consideration.
+ * if <method> is COMPLEX, a pseudorandom sequence is used to alter the
+ * CryptMask.This can make prediction well-nigh impossible.
+ */
+extern void cryptstr(Common::String &s);
+
+} // End of namespace Archetype
+} // End of namespace Glk
+
+#endif