feat: finish p18, implment aes ctr mode

common/src/lib.rs

@@ -482,3 +482,23 @@ pub fn gen_random_key() -> [u8; 16] {
     rng.fill(&mut key);
     key
 }
+
+pub fn aes_ctr_enc(input: &[u8], key: &[u8; 16], nonce: u64) -> Result<Vec<u8>> {
+    let mut key_stream = Vec::new();
+    for round in 0..=(input.len() / 16) as u64 {
+        let input: Vec<u8> = nonce
+            .to_le_bytes()
+            .into_iter()
+            .chain(round.to_le_bytes())
+            .collect();
+        let stream_block = aes_ecb_enc(&input, key)?;
+        key_stream.extend(stream_block);
+    }
+    let output: Vec<u8> = input.iter().zip(key_stream).map(|(&a, b)| a ^ b).collect();
+
+    Ok(output)
+}
+
+pub fn aes_ctr_dec(input: &[u8], key: &[u8; 16], nonce: u64) -> Result<Vec<u8>> {
+    aes_ctr_enc(input, key, nonce)
+}