Latest commit 2abfae2 Jan 20, 2017 @ncw crypt: fix crypt writer getting stuck in a loop #902
This happened when the underlying reader returned io.ErrUnexpectedEOF.
The error handling for the call to io.ReadFull failed to take this
into account.

io.ErrUnexpectedEOF is reasonably common when SSL connections go wrong
when communicating with ACD, so it manifested itself as transfers from
non-encrypted ACD to encrypted ACD getting stuck.