diff --git a/README.md b/README.md
index 37e0006..f88cf9d 100644
--- a/README.md
+++ b/README.md
@@ -43,6 +43,9 @@ You can then edit the `json` files to your willings.
 Calling the script again will produce new QR codes in the `out` folder which you
 can scan.
 
+WARNING: obviously, the `in`, `json` and `out` folders will contain sensitive data
+(your 2FA secrets). You will probably want to delete them after scanning into your app.
+
 
 [zbar]: https://github.com/mchehab/zbar
 [freeotp]: https://freeotp.github.io/