problem 11

1 files changed, 25 insertions, 1 deletions

diff --git a/src/aes.rs b/src/aes.rs
index 9baf595..e4a7184 100644
--- a/src/aes.rs
+++ b/src/aes.rs
@@ -1,8 +1,16 @@
-use openssl;
+use std;
 use std::collections::HashSet;
 
+use openssl;
+
 use primitives::{fixed_xor, pad_pkcs7, unpad_pkcs7};
 
+#[derive(PartialEq,Eq,Debug)]
+pub enum BlockCipherMode {
+    ECB,
+    CBC,
+}
+
 pub fn decrypt_aes_128_ecb (bytes: &[u8], key: &[u8]) -> Vec<u8> {
     return openssl::crypto::symm::decrypt(
         openssl::crypto::symm::Type::AES_128_ECB,
@@ -65,6 +73,22 @@ pub fn find_aes_128_ecb_encrypted_string (inputs: &[Vec<u8>]) -> Vec<u8> {
     return found;
 }
 
+pub fn detect_ecb_cbc<F> (f: F) -> BlockCipherMode where F: Fn(&[u8]) -> Vec<u8> {
+    let plaintext: Vec<u8> = (0..16)
+        .cycle()
+        .take(32)
+        .flat_map(|n| std::iter::repeat(n).take(17))
+        .collect();
+    let ciphertext = f(&plaintext[..]);
+
+    if count_duplicate_blocks(&ciphertext[..]) >= 16 {
+        return BlockCipherMode::ECB;
+    }
+    else {
+        return BlockCipherMode::CBC;
+    }
+}
+
 fn count_duplicate_blocks (input: &[u8]) -> usize {
     let mut set = HashSet::new();
     let mut dups = 0;