diff --git a/src/swab.rs b/src/swab.rs
index 2cd7800..2ea9fcc 100644
--- a/src/swab.rs
+++ b/src/swab.rs
@@ -33,7 +33,7 @@ use sysexits::{ EX_IOERR, EX_OK, EX_OSERR, EX_USAGE };
 use strerror::StrError;
 
 #[cfg(target_os="openbsd")] extern crate openbsd;
-#[cfg(target_os="openbsd")] use openbsd::{ Promises, pledge };
+#[cfg(target_os="openbsd")] use openbsd::{ Promises, pledge, unveil };
 
 fn err(argv0: &str, e: Error, code: u8) -> ExitCode {
 	eprintln!("{}: {}", argv0, e.strerror());
@@ -49,10 +49,14 @@ fn main() -> ExitCode {
 	let argv = args().collect::<Vec<String>>();
 	
 	#[cfg(target_os="openbsd")] {
-		let promises = Promises::new("stdio");
+		let promises = Promises::new("stdio unveil");
 		if let Err(e) = pledge(Some(promises), None) {
 			return err(&argv[0], e, EX_OSERR);
 		}
+
+		if let Err(e) = unveil(None, None) {
+			return err(&argv[0], e, EX_OSERR);
+		}
 	}
 
 	let mut buf: Vec<u8> = Vec::new(); // holds the sequence getting swabbed