diff --git a/lib/src/lib.rs b/lib/src/lib.rs
index c139a77..8122d73 100644
--- a/lib/src/lib.rs
+++ b/lib/src/lib.rs
@@ -73,6 +73,9 @@ impl FromStr for BytesPattern {
 
 impl From<(Vec<u8>, Vec<bool>)> for BytesPattern {
     fn from(x: (Vec<u8>, Vec<bool>)) -> Self {
+        if x.0.len() != x.1.len() {
+            panic!("mask length mismatch");
+        }
         let mut s = Self {
             bytes: x.0,
             mask: x.1,
@@ -255,4 +258,10 @@ mod tests {
         ];
         assert_eq!(mask, pattern.mask);
     }
+
+    #[test]
+    #[should_panic(expected = "mask length mismatch")]
+    fn pattern_from_tupple_wrong_mask_length() {
+        let _pattern = BytesPattern::from((vec![1u8, 2u8, 3u8], vec![true, false]));
+    }
 }