diff --git a/src/blowfish.c b/src/blowfish.c
index 01e0993..02d9008 100644
--- a/src/blowfish.c
+++ b/src/blowfish.c
@@ -542,7 +542,7 @@
     int i, mi;
 
     randbyte_offset = update_offset = 0;
-    memset(ofb_buffer, 0, BF_OFB_LEN);
+    vim_memset(ofb_buffer, 0, BF_OFB_LEN);
     if (iv_len > 0)
     {
 	mi = iv_len > BF_OFB_LEN ? iv_len : BF_OFB_LEN;