diff --git a/src/libsodium/crypto_onetimeauth/poly1305/onetimeauth_poly1305_try.c b/src/libsodium/crypto_onetimeauth/poly1305/onetimeauth_poly1305_try.c
index 6e242d22..82d67867 100644
--- a/src/libsodium/crypto_onetimeauth/poly1305/onetimeauth_poly1305_try.c
+++ b/src/libsodium/crypto_onetimeauth/poly1305/onetimeauth_poly1305_try.c
@@ -47,6 +47,11 @@ deallocate(void)
     free(k2_);
 }
 
+#ifdef HAVE_ARC4RANDOM
+# undef rand
+# define rand(X) arc4random(X)
+#endif
+
 static const char *
 checksum_compute(void)
 {