diff --git a/crates/util/keyfork-entropy/src/main.rs b/crates/util/keyfork-entropy/src/main.rs
index 7f36aab..22e6d5a 100644
--- a/crates/util/keyfork-entropy/src/main.rs
+++ b/crates/util/keyfork-entropy/src/main.rs
@@ -10,6 +10,10 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         bit_size % 8 == 0,
         "Bit size must be divisible by 8, got: {bit_size}"
     );
+    assert!(
+        bit_size >= 128,
+        "Minimum supported bit size is 128, got {bit_size}"
+    );
     match bit_size {
         128 | 256 | 512 => {}
         _ => {