diff --git a/src/headers/tomcrypt_custom.h b/src/headers/tomcrypt_custom.h
index 33e4bc0..6d6f4f3 100644
--- a/src/headers/tomcrypt_custom.h
+++ b/src/headers/tomcrypt_custom.h
@@ -304,6 +304,9 @@
 /* rng_make_prng() */
 #define LTC_RNG_MAKE_PRNG
 
+/* enable the ltc_rng hook to integrate e.g. embedded hardware RNG's easily */
+/* #define LTC_PRNG_ENABLE_LTC_RNG */
+
 #endif /* LTC_NO_PRNGS */
 
 #ifdef LTC_YARROW
diff --git a/src/headers/tomcrypt_prng.h b/src/headers/tomcrypt_prng.h
index 2bfe820..dc2cc7e 100644
--- a/src/headers/tomcrypt_prng.h
+++ b/src/headers/tomcrypt_prng.h
@@ -193,8 +193,10 @@ unsigned long rng_get_bytes(unsigned char *out,
 
 int rng_make_prng(int bits, int wprng, prng_state *prng, void (*callback)(void));
 
+#ifdef LTC_PRNG_ENABLE_LTC_RNG
 extern unsigned long (*ltc_rng)(unsigned char *out, unsigned long outlen,
       void (*callback)(void));
+#endif
 
 
 /* $Source$ */
diff --git a/src/misc/crypt/crypt.c b/src/misc/crypt/crypt.c
index 7d03cfa..aef292f 100644
--- a/src/misc/crypt/crypt.c
+++ b/src/misc/crypt/crypt.c
@@ -371,6 +371,9 @@ const char *crypt_build_settings =
 #if defined(LTC_RNG_MAKE_PRNG)
     " LTC_RNG_MAKE_PRNG "
 #endif
+#if defined(LTC_PRNG_ENABLE_LTC_RNG)
+    " LTC_PRNG_ENABLE_LTC_RNG "
+#endif
 #if defined(LTC_HASH_HELPERS)
     " LTC_HASH_HELPERS "
 #endif
diff --git a/src/misc/crypt/crypt_prng_rng_descriptor.c b/src/misc/crypt/crypt_prng_rng_descriptor.c
index 14f36ff..bf31781 100644
--- a/src/misc/crypt/crypt_prng_rng_descriptor.c
+++ b/src/misc/crypt/crypt_prng_rng_descriptor.c
@@ -10,4 +10,6 @@
  */
 #include "tomcrypt.h"
 
+#ifdef LTC_PRNG_ENABLE_LTC_RNG
 unsigned long (*ltc_rng)(unsigned char *out, unsigned long outlen, void (*callback)(void));
+#endif
diff --git a/src/prngs/rng_get_bytes.c b/src/prngs/rng_get_bytes.c
index 7430feb..28e8585 100644
--- a/src/prngs/rng_get_bytes.c
+++ b/src/prngs/rng_get_bytes.c
@@ -135,12 +135,14 @@ unsigned long rng_get_bytes(unsigned char *out, unsigned long outlen,
 
    LTC_ARGCHK(out != NULL);
 
+#ifdef LTC_PRNG_ENABLE_LTC_RNG
    if (ltc_rng) {
       x = ltc_rng(out, outlen, callback);
       if (x != 0) {
          return x;
       }
    }
+#endif
 
 #if defined(_WIN32) || defined(_WIN32_WCE)
    x = rng_win32(out, outlen, callback); if (x != 0) { return x; }
diff --git a/testprof/x86_prof.c b/testprof/x86_prof.c
index 4aee85c..2d4700f 100644
--- a/testprof/x86_prof.c
+++ b/testprof/x86_prof.c
@@ -302,6 +302,8 @@ static void _unregister_all(void)
 #endif
 } /* _cleanup() */
 
+#ifdef LTC_PRNG_ENABLE_LTC_RNG
+
 static unsigned long my_test_rng_read;
 
 static unsigned long my_test_rng(unsigned char *buf, unsigned long len,
@@ -316,6 +318,8 @@ static unsigned long my_test_rng(unsigned char *buf, unsigned long len,
    return n;
 }
 
+#endif
+
 void reg_algs(void)
 {
   unsigned long before;
@@ -456,6 +460,7 @@ register_prng(&rc4_desc);
 register_prng(&sober128_desc);
 #endif
 
+#ifdef LTC_PRNG_ENABLE_LTC_RNG
    ltc_rng = my_test_rng;
 
    before = my_test_rng_read;
@@ -470,6 +475,7 @@ register_prng(&sober128_desc);
    }
 
    ltc_rng = NULL;
+#endif
 
    if ((err = rng_make_prng(128, find_prng("yarrow"), &yarrow_prng, NULL)) != CRYPT_OK) {
       fprintf(stderr, "rng_make_prng failed: %s\n", error_to_string(err));