diff --git a/src/main.rs b/src/main.rs
index 2017116..0415d95 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,20 +1,7 @@
 mod set1;
 
-use crate::set1::{base64_to_string, bytes_to_base64, to_bytes};
-
-fn test_set1() {
-    let input = to_bytes("49276d206b696c6c696e6720796f757220627261696e206c696b65206120706f69736f6e6f7573206d757368726f6f6d");
-    let expected = String::from("SSdtIGtpbGxpbmcgeW91ciBicmFpbiBsaWtlIGEgcG9pc29ub3VzIG11c2hyb29t");
-    match input {
-        Ok(bytes) => {
-            let output = base64_to_string(bytes_to_base64(bytes));
-            assert_eq!(output, expected);
-            println!("{:?}", output);
-        }
-        Err(e) => println!("Error: {:?}", e),
-    };
-}
+use crate::set1::challenge1;
 
 fn main() {
-    test_set1();
+    challenge1();
 }
diff --git a/src/set1.rs b/src/set1.rs
index 1112a96..ab3580c 100644
--- a/src/set1.rs
+++ b/src/set1.rs
@@ -1,65 +1,122 @@
 use std::num::ParseIntError;
 use std::str;
 
-pub fn to_bytes(s: &str) -> Result<Vec<u8>, String> {
-    if s.len() % 2 != 0 {
-        return Err(String::from("Input string has uneven number of characters"));
-    }
+pub struct HexBytes(Vec<u8>);
+pub struct Base64Bytes(Vec<u8>);
 
-    let bytes_result: Result<Vec<u8>, ParseIntError> = (0..s.len())
-        .step_by(2)
-        .map(|i| u8::from_str_radix(&s[i..i + 2], 16))
-        .collect();
-
-    match bytes_result {
-        Ok(b) => Ok(b),
-        Err(_) => Err(String::from("Could not convert all digit pairs to hex.")),
-    }
-}
-
-fn chunk_to_base64(c: &[u8]) -> Vec<u8> {
-    let (value, iterations) = match c.len() {
-        0 => return vec![],
-        1 => ((c[0] as u32) << 16, 2),
-        2 => ((c[0] as u32) << 16 | (c[1] as u32) << 8, 3),
-        3 => ((c[0] as u32) << 16 | (c[1] as u32) << 8 | (c[2] as u32), 4),
-        _ => panic!("Unexpected number of chunks {}.", c.len()),
-    };
-    (0..iterations)
-        .map(|i| (value.rotate_right((3 - i) * 6) & 0b111111) as u8)
-        .collect()
-}
-
-pub fn bytes_to_base64(bytes: Vec<u8>) -> Vec<u8> {
-    bytes
-        .chunks(3)
-        .map(|c| chunk_to_base64(c))
-        .flatten()
-        .collect()
-}
-
-pub fn base64_to_string(digits: Vec<u8>) -> String {
-    let mut r: Vec<u8> = digits
-        .iter()
-        .map(|d| match d {
-            0..=25 => *d + ('A' as u8),
-            26..=51 => *d - 26 + ('a' as u8),
-            52..=61 => *d - 52 + ('0' as u8),
-            62 => '+' as u8,
-            63 => '/' as u8,
-            _ => panic!("Unexpected base64 digit '{}'", d),
-        })
-        .collect();
-    // Handle padding
-    let pad = '=' as u8;
-    match r.len() % 4 {
-        0 => (),
-        2 => {
-            r.push(pad);
-            r.push(pad);
+impl std::fmt::Display for Base64Bytes {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let Base64Bytes(digits) = self;
+        let mut r: Vec<u8> = digits
+            .iter()
+            .map(|d| match d {
+                0..=25 => *d + ('A' as u8),
+                26..=51 => *d - 26 + ('a' as u8),
+                52..=61 => *d - 52 + ('0' as u8),
+                62 => '+' as u8,
+                63 => '/' as u8,
+                _ => panic!("Unexpected base64 digit '{}'", d),
+            })
+            .collect();
+        // Handle padding
+        let pad = '=' as u8;
+        match r.len() % 4 {
+            0 => (),
+            2 => {
+                r.push(pad);
+                r.push(pad);
+            }
+            3 => r.push(pad),
+            _ => (),
         }
-        3 => r.push(pad),
-        _ => (),
+
+        write!(f, "Base64({})", str::from_utf8(r.as_slice()).unwrap())
     }
-    str::from_utf8(r.as_slice()).unwrap().to_string()
+}
+
+impl Base64Bytes {
+    pub fn to_string(&self) -> String {
+        let Base64Bytes(digits) = self;
+        let mut r: Vec<u8> = digits
+            .iter()
+            .map(|d| match d {
+                0..=25 => *d + ('A' as u8),
+                26..=51 => *d - 26 + ('a' as u8),
+                52..=61 => *d - 52 + ('0' as u8),
+                62 => '+' as u8,
+                63 => '/' as u8,
+                _ => panic!("Unexpected base64 digit '{}'", d),
+            })
+            .collect();
+        // Handle padding
+        let pad = '=' as u8;
+        match r.len() % 4 {
+            0 => (),
+            2 => {
+                r.push(pad);
+                r.push(pad);
+            }
+            3 => r.push(pad),
+            _ => (),
+        }
+        str::from_utf8(r.as_slice()).unwrap().to_string()
+    }
+}
+
+impl HexBytes {
+    pub fn to_base64(&self) -> Base64Bytes {
+        fn chunk_to_base64(c: &[u8]) -> Vec<u8> {
+            let (value, iterations) = match c.len() {
+                0 => return vec![],
+                1 => ((c[0] as u32) << 16, 2),
+                2 => ((c[0] as u32) << 16 | (c[1] as u32) << 8, 3),
+                3 => ((c[0] as u32) << 16 | (c[1] as u32) << 8 | (c[2] as u32), 4),
+                _ => panic!("Unexpected number of chunks {}.", c.len()),
+            };
+
+            (0..iterations)
+                .map(|i| (value.rotate_right((3 - i) * 6) & 0b111111) as u8)
+                .collect()
+        }
+        let HexBytes(bytes) = self;
+        Base64Bytes(
+            bytes
+                .chunks(3)
+                .map(|c| chunk_to_base64(c))
+                .flatten()
+                .collect(),
+        )
+    }
+
+    pub fn from_str(s: &str) -> Result<HexBytes, String> {
+        if s.len() % 2 != 0 {
+            return Err(String::from("Input string has uneven number of characters"));
+        }
+
+        let bytes_result: Result<Vec<u8>, ParseIntError> = (0..s.len())
+            .step_by(2)
+            .map(|i| u8::from_str_radix(&s[i..i + 2], 16))
+            .collect();
+
+        match bytes_result {
+            Ok(b) => Ok(HexBytes(b)),
+            Err(_) => Err(String::from("Could not convert all digit pairs to hex.")),
+        }
+    }
+}
+
+pub fn challenge1() {
+    let input = HexBytes::from_str("49276d206b696c6c696e6720796f757220627261696e206c696b65206120706f69736f6e6f7573206d757368726f6f6d");
+    let expected = String::from("SSdtIGtpbGxpbmcgeW91ciBicmFpbiBsaWtlIGEgcG9pc29ub3VzIG11c2hyb29t");
+    match input {
+        Ok(bytes) => {
+            let output = bytes.to_base64();
+            if output.to_string() != expected {
+                println!("HexBytes.to_base64 failed.")
+            } else {
+                println!("[okay] Challenge 1: {}", output);
+            }
+        }
+        Err(e) => println!("Error: {}", e),
+    };
 }