Is there any software available for testing of Bitcoin security? I'm currently in the process of working on my thesis about Bitcoin security and I'm wondering if there's any software available for testing of Bitcoin security? For example, are there any programs that will try launching double-spend attacks, simulate a 51% attack, or the like?
testnet-in-a-box is a simple way to set up your own testnet network, separate from the main one.  That lets you mine your own blocks easily because the difficulty will stay low.  Then you can play around with double-spending your own coins to yourself without inconveniencing others, and without needing large amounts of hash power.