diff --git a/demos/timing.c b/demos/timing.c
index 746055d..1b74af9 100644
--- a/demos/timing.c
+++ b/demos/timing.c
@@ -919,7 +919,7 @@ static void time_dh(void)
            dh_free(&key);
        }
        t2 >>= 4;
-       fprintf(stderr, "DH-%4lu make_key    took %15llu cycles\n", x*8, t2);
+       fprintf(stderr, "DH-%4lu make_key    took %15"PRI64"u cycles\n", x*8, t2);
   }
 }
 #else
diff --git a/src/headers/tomcrypt_math.h b/src/headers/tomcrypt_math.h
index a52fb9d..b655346 100644
--- a/src/headers/tomcrypt_math.h
+++ b/src/headers/tomcrypt_math.h
@@ -30,7 +30,7 @@
    #define LTC_MILLER_RABIN_REPS    35
 #endif
 
-int radix_to_bin(const void *in, int radix, void *out, size_t* len);
+int radix_to_bin(const void *in, int radix, void *out, unsigned long *len);
 
 /** math descriptor */
 typedef struct {
diff --git a/src/math/radix_to_bin.c b/src/math/radix_to_bin.c
index fef58ae..409bd20 100644
--- a/src/math/radix_to_bin.c
+++ b/src/math/radix_to_bin.c
@@ -31,9 +31,9 @@
 
    @return CRYPT_OK on success.
 */
-int radix_to_bin(const void *in, int radix, void *out, size_t* len)
+int radix_to_bin(const void *in, int radix, void *out, unsigned long *len)
 {
-   size_t l;
+   unsigned long l;
    void* mpi;
    int err;