From 7bcdc3b4ca460aec2b98fb2dca6165788c562b05 Mon Sep 17 00:00:00 2001
From: Igor Tolmachev <me@igorek.dev>
Date: Sat, 20 Jul 2024 16:52:39 +0900
Subject: Partial aes implementation and others improvements

---
 src/zip/encryption/aes.rs | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 src/zip/encryption/aes.rs

(limited to 'src/zip/encryption/aes.rs')

diff --git a/src/zip/encryption/aes.rs b/src/zip/encryption/aes.rs
new file mode 100644
index 0000000..6f41aaa
--- /dev/null
+++ b/src/zip/encryption/aes.rs
@@ -0,0 +1,46 @@
+use crate::utils::ReadUtils;
+use aes::cipher::generic_array::GenericArray;
+use aes::cipher::BlockEncrypt;
+use std::io::{Read, Result as IoResult};
+
+#[allow(dead_code)]
+pub struct AesDecoder<Io: Read, Aes: BlockEncrypt> {
+    io: Io,
+    aes: Aes,
+
+    counter: u128,
+    block: [u8; 16],
+    cursor: usize,
+}
+
+impl<Io: Read, Aes: BlockEncrypt> AesDecoder<Io, Aes> {
+    pub fn new(mut io: Io, aes: Aes) -> IoResult<Self> {
+        let block = io.read_arr::<16>()?;
+        let mut decoder = Self {
+            io,
+            aes,
+            counter: 1,
+            block,
+            cursor: 0,
+        };
+        decoder.decrypt_block();
+        Ok(decoder)
+    }
+
+    #[inline]
+    fn decrypt_block(&mut self) {
+        let mut mask = self.counter.to_le_bytes();
+        self.aes
+            .encrypt_block(GenericArray::from_mut_slice(&mut mask));
+        for (b, m) in self.block.iter_mut().zip(mask) {
+            *b ^= m
+        }
+        self.counter += 1;
+    }
+}
+
+impl<Io: Read, Aes: BlockEncrypt> Read for AesDecoder<Io, Aes> {
+    fn read(&mut self, buf: &mut [u8]) -> IoResult<usize> {
+        todo!()
+    }
+}
-- 
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