diff --git a/examples/hmac_sha1.rs b/examples/hmac_sha1.rs
new file mode 100644
index 0000000..59f8b28
--- /dev/null
+++ b/examples/hmac_sha1.rs
@@ -0,0 +1,31 @@
+use rust_util::{opt_result, XResult};
+use yubico_manager::hmacmode::HmacKey;
+use yubico_manager::sec::hmac_sha1;
+
+fn main() -> XResult<()> {
+    let args: Vec<String> = std::env::args().skip(1).collect();
+
+    if args.len() != 2 && args.len() != 3 {
+        println!("cargo r --example hmac_sha1 <hmac_key_hex;20bytes> <challenge_hex> [variable;bool]");
+        return Ok(());
+    }
+
+    let hmac_key_bytes = opt_result!(hex::decode(&args[0]), "Decode hmac key hex failed: {}");
+    let challenge_bytes = opt_result!(hex::decode(&args[1]), "Decode challenge hex failed: {}");
+    let variable = if args.len() == 3 { "true" == &args[2] } else { false };
+
+    let hmac_key = HmacKey::from_slice(&hmac_key_bytes);
+
+    let mut challenge = [0; 64];
+    if variable && challenge_bytes.last() == Some(&0) {
+        challenge = [0xff; 64];
+    }
+    (&mut challenge[..challenge_bytes.len()]).copy_from_slice(&challenge_bytes);
+
+    let hmac_sha_result = hmac_sha1(&hmac_key, &challenge);
+
+    println!("Variable: {}", variable);
+    println!("Hmac challenge: {}", hex::encode(&challenge));
+    println!("Hmac_Sha1: {}", hex::encode(&hmac_sha_result));
+    Ok(())
+}
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