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diff --git a/bertos/sec/prng/isaac.h b/bertos/sec/prng/isaac.h
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+/**
+ * \file
+ * <!--
+ * This file is part of BeRTOS.
+ *
+ * Bertos 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 St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * As a special exception, you may use this file as part of a free software
+ * library without restriction.  Specifically, if other files instantiate
+ * templates or use macros or inline functions from this file, or you compile
+ * this file and link it with other files to produce an executable, this
+ * file does not by itself cause the resulting executable to be covered by
+ * the GNU General Public License.  This exception does not however
+ * invalidate any other reasons why the executable file might be covered by
+ * the GNU General Public License.
+ *
+ * Copyright 2010 Develer S.r.l. (http://www.develer.com/)
+ *
+ * -->
+ *
+ * \brief ISAAC implementation
+ * \author Giovanni Bajo <rasky@develer.com>
+ * 
+ */
+
+#ifndef SEC_PRNG_ISAAC_H
+#define SEC_PRNG_ISAAC_H
+
+#include <sec/prng.h>
+
+/**
+ * Size of the internal ISAAC state (in 32-bit words).
+ * 
+ * ISAAC is known to generate unbiased data as follows:
+ *   * 3 words: 2^37 unbiased values
+ *   * 4 words: 2^45 unbiased values
+ *   * 5 words: 2^53 unbiased values
+ *   * 6 words: 2^61 unbiased values
+ *   * 7 words: 2^69 unbiased values
+ *   * 8 words: 2^77 unbiased values
+ * 
+ * The period of the generator is usually much longer, but it is
+ * obviously uninteresting for a CSPRNG.
+ */
+#define CONFIG_ISAAC_RANDSIZL   (3)
+#define CONFIG_ISAAC_RANDSIZ    (1<<(CONFIG_ISAAC_RANDSIZL))
+
+typedef struct
+{
+	PRNG prng;
+	uint32_t randcnt;
+	uint32_t randrsl[CONFIG_ISAAC_RANDSIZ];
+	uint32_t randmem[CONFIG_ISAAC_RANDSIZ];
+	uint32_t randa;
+	uint32_t randb;
+	uint32_t randc;
+} ISAAC_Context;
+
+void ISAAC_init(ISAAC_Context *ctx);
+
+#define ISAAC_stackinit(...) \
+	({ ISAAC_Context *ctx = alloca(sizeof(ISAAC_Context)); ISAAC_init(ctx , ##__VA_ARGS__); &ctx->prng; })
+
+
+#endif /* SEC_PRNG_ISAAC_H */