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+/* arcfour.h --- The arcfour stream cipher
+ * Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005
+ *    Free Software Foundation, Inc.
+ *
+ * This file 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, or (at your
+ * option) any later version.
+ *
+ * This file 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 file; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ */
+
+/* Code from Libgcrypt adapted for gnulib by Simon Josefsson. */
+
+#ifndef ARCFOUR_H
+# define ARCFOUR_H
+
+# include <stddef.h>
+
+#define ARCFOUR_SBOX_SIZE 256
+
+typedef struct
+{
+  size_t idx_i, idx_j;
+  char sbox[ARCFOUR_SBOX_SIZE];
+} arcfour_context;
+
+/* Apply ARCFOUR stream to INBUF placing the result in OUTBUF, both of
+   LENGTH size.  CONTEXT must be initialized with arcfour_setkey
+   before this function is called. */
+extern void
+arcfour_stream (arcfour_context * context,
+		const char *inbuf, char *outbuf, size_t length);
+
+/* Initialize CONTEXT using encryption KEY of KEYLEN bytes.  KEY
+   should be 40 bits (5 bytes) or longer.  The KEY cannot be zero
+   length.  */
+extern void
+arcfour_setkey (arcfour_context * context, const char *key, size_t keylen);
+
+#endif /* ARCFOUR_H */