--- /dev/null
+/* 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.
+ */
+#include "tomcrypt.h"
+
+#ifdef LTC_RNG_MAKE_PRNG
+/**
+ @file rng_make_prng.c
+ portable way to get secure random bits to feed a PRNG (Tom St Denis)
+*/
+
+/**
+ Create a PRNG from a RNG
+ @param bits Number of bits of entropy desired (64 ... 1024)
+ @param wprng Index of which PRNG to setup
+ @param prng [out] PRNG state to initialize
+ @param callback A pointer to a void function for when the RNG is slow, this can be NULL
+ @return CRYPT_OK if successful
+*/
+int rng_make_prng(int bits, int wprng, prng_state *prng,
+ void (*callback)(void))
+{
+ unsigned char buf[256];
+ int err;
+
+ LTC_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 LTC_CLEAN_STACK
+ zeromem(buf, sizeof(buf));
+ #endif
+ return CRYPT_OK;
+}
+#endif /* #ifdef LTC_RNG_MAKE_PRNG */
+
+
+/* ref: $Format:%D$ */
+/* git commit: $Format:%H$ */
+/* commit time: $Format:%ai$ */