diff rng_make_prng.c @ 0:d7da3b1e1540 libtomcrypt

put back the 0.95 makefile which was inadvertently merged over
author Matt Johnston <matt@ucc.asn.au>
date Mon, 31 May 2004 18:21:40 +0000
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rng_make_prng.c	Mon May 31 18:21:40 2004 +0000
@@ -0,0 +1,53 @@
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, [email protected], http://libtomcrypt.org
+ */
+/* portable way to get secure random bits to feed a PRNG */
+#include "mycrypt.h"
+
+int rng_make_prng(int bits, int wprng, prng_state *prng, 
+                  void (*callback)(void))
+{
+   unsigned char buf[256];
+   int err;
+   
+   _ARGCHK(prng != NULL);
+
+   /* check parameter */
+   if ((err = prng_is_valid(wprng)) != CRYPT_OK) {
+      return err;
+   }
+
+   if (bits < 64 || bits > 1024) {
+      return CRYPT_INVALID_PRNGSIZE;
+   }
+
+   if ((err = prng_descriptor[wprng].start(prng)) != CRYPT_OK) {
+      return err;
+   }
+
+   bits = ((bits/8)+((bits&7)!=0?1:0)) * 2;
+   if (rng_get_bytes(buf, (unsigned long)bits, callback) != (unsigned long)bits) {
+      return CRYPT_ERROR_READPRNG;
+   }
+
+   if ((err = prng_descriptor[wprng].add_entropy(buf, (unsigned long)bits, prng)) != CRYPT_OK) {
+      return err;
+   }
+
+   if ((err = prng_descriptor[wprng].ready(prng)) != CRYPT_OK) {
+      return err;
+   }
+
+   #ifdef CLEAN_STACK
+      zeromem(buf, sizeof(buf));
+   #endif
+   return CRYPT_OK;
+}
+