Here is a list of references regarding security topics and hacktivism:
Here are several awesome organization regarding online freedom:
EFF : The Electronic Frontier Foundation fights for digital freedom in many different ways (legal fights, press review, development of technical tools…). See their website and their Twitter account. Here is a list of EFF projects I like:
Citizen Lab is a research group based in the University of Toronto which focus its researchs on human rights and digital surveillance. They have done amazing analysis of targeted attacks by governments on citizen (like this one or this one). See their website or twitter account.