+PeerConnectionBase::initialize(DownloadMain* download, PeerInfo* peerInfo, SocketFd fd, Bitfield* bitfield, std::auto_ptr<RC4> encrypt, std::auto_ptr<RC4> decrypt) {

Consider passing just pointers, and then copy-by-value. Thus Handshake and PCB can have the member as a value rather than a pointer.


    if (length > m_encryptBuffer->size_end()) {
      length -= m_encryptBuffer->size_end();

WTF, need to look at this when i'm not tipsy. Does it fill the entire chunk into the buffer?


-        m_down->buffer()->move_end(read_stream_throws(m_down->buffer()->end(), read_size - m_down->buffer()->size_end()));
+        unsigned int read;
+        read = read_stream_throws(m_down->buffer()->end(), read_size - m_down->buffer()->size_end());
+        if (is_encrypted())
+          m_decrypt->crypt(m_down->buffer()->end(), read);
+        m_down->buffer()->move_end(read);

Add an inline helper function for readning encrypted data.


The handshake error messages should be similar to errno, with an strerror'ish func in ConnectionManager.


+  if ((h->encryption_options() & ConnectionManager::encryption_enable_retry) != 0 && h->get_retry_type() != Handshake::RETRY_NONE) {

Store the retry options in Handshake, instead of using new enums. Just check if it is a valid retry flag.