Getting a Keeloq manufacturer key
There have been several attacks against Keeloq.  I cannot speak to the specific algorithm changes through the years to make it stronger against brute force; however, I am knowledgable in the hardware changes as of discussions I was privy to in 2009.   The Keeloq ICs were changed shortly after the power attacks came out to make them immune from power attacks through the use of dual rail encoding.  At the time, the core of the Keeloq ICs are based on the PIC12, which are very simple and could allow power attacks if you could instruction step them. Through dual rail encoding, you use the same amount of power in all data cases, but not necessarily instruction cases.   Even though the PIC12s are only one-time-programmable, you can still hook them onto a debugger to single-step them.  If you are interested on how this could be done, see if you can get the course notes from Tom Collins for his lab.