The DMCA protects (cf. Fair Use) research of any software system (including reversing) for the purposes of interoperability. This is how security researchers survive... If I'm interested in discussing how an existing security system works to understand how I can inter-operate with it from a software standpoint (or even if I simply want to understand it so I can learn from it), is this the appropriate forum for that? Does it matter if the system is proprietary or not as far as this community here is concerned (the DCMA says, "no")?
As far as the security part goes, yes it is on topic. The tricky bit though is having an actual question - SE isn't really built for discussions. If you have a specific question (and a security question, not just a question about a security system), go right ahead.
If you're not sure, you can ask here if the specific question is a good fit...