Mixing Networks are protocols that allow a set of senders to send messages anonymously. Such protocols are fundamental building blocks to achieve privacy in a variety of applications, such as anonymous e-mail, anonymous payments, and electronic voting. Back in 2002, Golle et al. proposed a new concept of mixing network, called optimistic mixing, that allows for fast mixing when all the parties execute the protocol honestly. If, on the other hand, one or more mix-servers cheat, then the attack is recognized and one can back up to a different, slow mix-net. Unfortunately, Abe and Imai (ACISP’03) and independently Wikström (SAC’03) showed several major flaws in the optimistic protocol of Golle et al. In this talk we give another look at optimistic mixing networks. I will introduce the concept of secure optimistic mixing and show a simple construction based on a new re-randomizable encryption scheme.