Lots of stuff

src/audio_decrypt.rs

@@ -0,0 +1,54 @@
+use crypto::aes;
+use crypto::symmetriccipher::SynchronousStreamCipher;
+use readall::ReadAllExt;
+use std::io;
+
+use audio_key::AudioKey;
+
+const AUDIO_AESIV : &'static [u8] = &[
+    0x72,0xe0,0x67,0xfb,0xdd,0xcb,0xcf,0x77,0xeb,0xe8,0xbc,0x64,0x3f,0x63,0x0d,0x93,
+];
+
+pub struct AudioDecrypt<T : io::Read> {
+    cipher: Box<SynchronousStreamCipher + 'static>,
+    key: AudioKey,
+    reader: T,
+}
+
+impl <T : io::Read> AudioDecrypt<T> {
+    pub fn new(key: AudioKey, mut reader: T) -> AudioDecrypt<T> {
+        let mut cipher = aes::ctr(aes::KeySize::KeySize128,
+                              &key,
+                              AUDIO_AESIV);
+
+        let mut buf = [0; 0xa7];
+        let mut buf2 = [0; 0xa7];
+        reader.read_all(&mut buf).unwrap();
+        cipher.process(&buf, &mut buf2);
+
+        AudioDecrypt {
+            cipher: cipher,
+            key: key,
+            reader: reader,
+        }
+    }
+}
+
+impl <T : io::Read> io::Read for AudioDecrypt<T> {
+    fn read(&mut self, output: &mut [u8]) -> io::Result<usize> {
+        let mut buffer = vec![0u8; output.len()];
+        let len = try!(self.reader.read(&mut buffer));
+
+        self.cipher.process(&buffer[..len], &mut output[..len]);
+
+        Ok(len)
+    }
+}
+
+impl <T : io::Read> io::Seek for AudioDecrypt<T> {
+    fn seek(&mut self, _pos: io::SeekFrom) -> io::Result<u64> {
+        Err(io::Error::new(io::ErrorKind::Other, "Cannot seek"))
+    }
+}
+
+