diff --git a/src/md4.rs b/src/md4.rs
index a993b21..1245bd7 100644
--- a/src/md4.rs
+++ b/src/md4.rs
@@ -62,30 +62,30 @@ impl Md4Core {
 }
 
 fn compress(state: &mut [u32; 4], input: &[u8; BLOCK_BYTES]) {
-    fn f(x: u32, y: u32, z: u32) -> u32 {
+    const fn f(x: u32, y: u32, z: u32) -> u32 {
         (x & y) | (!x & z)
     }
 
-    fn g(x: u32, y: u32, z: u32) -> u32 {
+    const fn g(x: u32, y: u32, z: u32) -> u32 {
         (x & y) | (x & z) | (y & z)
     }
 
-    fn h(x: u32, y: u32, z: u32) -> u32 {
+    const fn h(x: u32, y: u32, z: u32) -> u32 {
         x ^ y ^ z
     }
 
-    fn op1(a: u32, b: u32, c: u32, d: u32, k: u32, s: u32) -> u32 {
+    const fn op1(a: u32, b: u32, c: u32, d: u32, k: u32, s: u32) -> u32 {
         a.wrapping_add(f(b, c, d)).wrapping_add(k).rotate_left(s)
     }
 
-    fn op2(a: u32, b: u32, c: u32, d: u32, k: u32, s: u32) -> u32 {
+    const fn op2(a: u32, b: u32, c: u32, d: u32, k: u32, s: u32) -> u32 {
         a.wrapping_add(g(b, c, d))
             .wrapping_add(k)
             .wrapping_add(0x5A82_7999)
             .rotate_left(s)
     }
 
-    fn op3(a: u32, b: u32, c: u32, d: u32, k: u32, s: u32) -> u32 {
+    const fn op3(a: u32, b: u32, c: u32, d: u32, k: u32, s: u32) -> u32 {
         a.wrapping_add(h(b, c, d))
             .wrapping_add(k)
             .wrapping_add(0x6ED9_EBA1)
diff --git a/src/set1.rs b/src/set1.rs
index 11aaf50..5bf14b8 100644
--- a/src/set1.rs
+++ b/src/set1.rs
@@ -10,7 +10,7 @@ pub fn challenge1() {
     let expected = String::from("SSdtIGtpbGxpbmcgeW91ciBicmFpbiBsaWtlIGEgcG9pc29ub3VzIG11c2hyb29t");
     let result = BytesBase64::from_bytes(input);
     if result.to_string() == expected {
-        println!("[okay] Challenge 1: {}", result);
+        println!("[okay] Challenge 1: {result}");
     } else {
         println!("[fail] Challenge 1");
     }
@@ -34,7 +34,7 @@ pub fn challenge3() {
     h.sort_by(|a, b| a.ascii_score().partial_cmp(&b.ascii_score()).unwrap());
     // let h: Vec<Bytes> = h.into_iter().filter(|b| b.is_ascii()).collect();
     let r = h.last().unwrap().to_utf8();
-    println!("[okay] Challenge 3: {}", r);
+    println!("[okay] Challenge 3: {r}");
 }
 
 pub fn challenge4() {
@@ -133,7 +133,7 @@ pub fn challenge6() {
     let msg = Bytes::xor_cycle(&bytes, &key).to_utf8();
 
     let partial_msg = msg[..20].to_string();
-    println!("[okay] Challenge 6: {}...", partial_msg);
+    println!("[okay] Challenge 6: {partial_msg}...");
 }
 
 pub fn challenge7() {
@@ -145,7 +145,7 @@ pub fn challenge7() {
     let ciphertext = utils::read_base64("data/7.txt");
     let data = ecb::decrypt(&key, &ciphertext);
     let partial_msg = data.to_utf8()[..20].to_string();
-    println!("[okay] Challenge 7: {}...", partial_msg);
+    println!("[okay] Challenge 7: {partial_msg}...");
 }
 
 pub fn challenge8() {
diff --git a/src/set2.rs b/src/set2.rs
index 6181025..484bee2 100644
--- a/src/set2.rs
+++ b/src/set2.rs
@@ -375,7 +375,7 @@ pub fn challenge16() {
     fn encrypt(input: &str, key: &Bytes, iv: &Bytes) -> Bytes {
         let mut r = String::new();
         for c in input.chars() {
-            assert!(c != ';' && c != '=', "encrypt: invalid char {}", c);
+            assert!(c != ';' && c != '=', "encrypt: invalid char {c}");
         }
         r.push_str("comment1=cooking%20MCs;userdata=");
         r.push_str(input);
@@ -402,5 +402,5 @@ pub fn challenge16() {
     let dict = parser::parse_key_value(&cleartext_stripped.to_utf8());
     let admin_status = dict.get("admin").unwrap();
     assert_eq!(admin_status, "true");
-    println!("[okay] Challenge 16: admin={}", admin_status);
+    println!("[okay] Challenge 16: admin={admin_status}");
 }