diff --git a/lib/md5.c b/lib/md5.c
index daab76c..893956d 100644
--- a/lib/md5.c
+++ b/lib/md5.c
@@ -134,7 +134,7 @@ MD5Final(md5byte digest[16], struct MD5Context *ctx)
 
 	byteSwap(ctx->buf, 4);
 	memcpy(digest, ctx->buf, 16);
-	memset(ctx, 0, sizeof(ctx));	/* In case it's sensitive */
+	memset(ctx, 0, sizeof(*ctx));	/* In case it's sensitive */
 }
 
 #ifndef ASM_MD5