Having finished this tutorial, you have received a good glimpse of many of the surprisingly powerful things that can be accomplished by combining cryptographic building blocks. On the other hand, you have also seen a few cases where mathematical facts limit the wished for -- and sometimes claimed -- capabilities of cryptography. The development of cryptological protocols is beautiful, fascinating, and even fun; but if you're interested, you should investigate further the mathematical and programming details in the Resources section to gain a more complete understanding of the subject.