Start with challenge 17.

src/set3.rs

@@ -0,0 +1,36 @@
+use crate::bytes::Bytes;
+use crate::bytes_base64::BytesBase64;
+use crate::cbc;
+use rand::Rng;
+use std::io::{BufRead, BufReader};
+
+pub fn challenge17() {
+    fn read(path: &str) -> Vec<Bytes> {
+        let file = std::fs::File::open(path).unwrap();
+        let br = BufReader::new(file);
+        br.lines()
+            .map(|line| BytesBase64::from_base64(&line.unwrap()).to_bytes())
+            .collect()
+    }
+
+    fn encrypt(ten_strings: &Vec<Bytes>, key: &Bytes) -> (Bytes, Bytes) {
+        // The first function should select at random one of the ten strings
+        let index: usize = rand::thread_rng().gen_range(0..ten_strings.len());
+        let mut cleartext = Bytes(ten_strings[index].0.to_vec());
+
+        // pad the string out to the 16-byte AES block size and
+        cleartext.pad_pkcs7(16);
+
+        // CBC-encrypt it under that key, providing the caller the ciphertext
+        // and IV.
+        let iv = Bytes::random(16);
+        (cbc::encrypt(&key, &iv, &cleartext), iv)
+    }
+    let cleartexts = read("data/17.txt");
+
+    // generate a random AES key (which it should save for all future encryptions)
+    let key = Bytes::random(16);
+    let (cipher, _iv) = encrypt(&cleartexts, &key);
+
+    println!("[xxxx] Challenge 17: {}", cipher.len());
+}