diff --git a/test/default/sodium_utils.c b/test/default/sodium_utils.c
index 63d5f091..bcf8bc0c 100644
--- a/test/default/sodium_utils.c
+++ b/test/default/sodium_utils.c
@@ -152,9 +152,9 @@ main(void)
     for (i = 0; i < 1000; i++) {
         assert(sizeof buf1 >= 100);
         bin_len = (size_t) randombytes_uniform(100);
-        bin = sodium_malloc(bin_len);
+        bin = (unsigned char *) sodium_malloc(bin_len);
         b64_len = 1 + (bin_len + 2) / 3 * 4;
-        b64_ = sodium_malloc(b64_len);
+        b64_ = (char *) sodium_malloc(b64_len);
         randombytes_buf(bin, bin_len);
         memcpy(buf1, bin, bin_len);
         b64 = sodium_bin2base64(b64_, b64_len, bin, bin_len,