diff --git a/library/platform_util.c b/library/platform_util.c
index 78f8e56..dad8376 100644
--- a/library/platform_util.c
+++ b/library/platform_util.c
@@ -84,7 +84,7 @@
     /* Randomize start offset. */
     size_t start_offset = (size_t) mbedtls_platform_random_in_range( num );
     /* Randomize data */
-    size_t data = (size_t) mbedtls_platform_random_in_range( 256 );
+    uint32_t data = mbedtls_platform_random_in_range( 256 );
 
     /* Perform a pair of memset operations from random locations with
      * random data */
@@ -101,7 +101,7 @@
     /* Randomize start offset. */
     size_t start_offset = (size_t) mbedtls_platform_random_in_range( num );
     /* Randomize initial data to prevent leakage while copying */
-    size_t data = (size_t) mbedtls_platform_random_in_range( 256 );
+    uint32_t data = mbedtls_platform_random_in_range( 256 );
 
     memset( (void *) dst, data, num );
     memcpy( (void *) ( (unsigned char *) dst + start_offset ),