--- /dev/null
+/*
+ ---------------------------------------------------------------------------
+ Copyright (c) 2002, Dr Brian Gladman < >, Worcester, UK.
+ All rights reserved.
+
+ LICENSE TERMS
+
+ The free distribution and use of this software in both source and binary
+ form is allowed (with or without changes) provided that:
+
+ 1. distributions of this source code include the above copyright
+ notice, this list of conditions and the following disclaimer;
+
+ 2. distributions in binary form include the above copyright
+ notice, this list of conditions and the following disclaimer
+ in the documentation and/or other associated materials;
+
+ 3. the copyright holder's name is not used to endorse products
+ built using this software without specific written permission.
+
+ ALTERNATIVELY, provided that this notice is retained in full, this product
+ may be distributed under the terms of the GNU General Public License (GPL),
+ in which case the provisions of the GPL apply INSTEAD OF those given above.
+
+ DISCLAIMER
+
+ This software is provided 'as is' with no explicit or implied warranties
+ in respect of its properties, including, but not limited to, correctness
+ and/or fitness for purpose.
+ ---------------------------------------------------------------------------
+ Issue Date: 24/01/2003
+
+ This is the header file for an implementation of a random data pool based on
+ the use of an external entropy function (inspired by Peter Gutmann's work).
+*/
+
+#ifndef _PRNG_H
+#define _PRNG_H
+
+#include "sha1.h"
+
+#define PRNG_POOL_LEN 256 /* minimum random pool size */
+#define PRNG_MIN_MIX 20 /* min initial pool mixing iterations */
+
+/* ensure that pool length is a multiple of the SHA1 digest size */
+
+#define PRNG_POOL_SIZE (SHA1_DIGEST_SIZE * (1 + (PRNG_POOL_LEN - 1) / SHA1_DIGEST_SIZE))
+
+#if defined(__cplusplus)
+extern "C"
+{
+#endif
+
+/* A function for providing entropy is a parameter in the prng_init() */
+/* call. This function has the following form and returns a maximum */
+/* of 'len' bytes of pseudo random data in the buffer 'buf'. It can */
+/* return less than 'len' bytes but will be repeatedly called for more */
+/* data in this case. */
+
+typedef int (*prng_entropy_fn)(unsigned char buf[], unsigned int len);
+
+typedef struct
+{ unsigned char rbuf[PRNG_POOL_SIZE]; /* the random pool */
+ unsigned char obuf[PRNG_POOL_SIZE]; /* pool output buffer */
+ unsigned int pos; /* output buffer position */
+ prng_entropy_fn entropy; /* entropy function pointer */
+} prng_ctx;
+
+/* initialise the random stream generator */
+void prng_init(prng_entropy_fn fun, prng_ctx ctx[1]);
+
+/* obtain random bytes from the generator */
+void prng_rand(unsigned char data[], unsigned int data_len, prng_ctx ctx[1]);
+
+/* close the random stream generator */
+void prng_end(prng_ctx ctx[1]);
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif