http://wikipewt4n75trifcse2ggaieot27svognl7idu6xmmqn37kf64rvsyd.onion/index.php/Intrusive_Surveillance
Note that if you destroy a key after a court demands to see it (or simply refuse to give up the password) you can be held in contempt of court and sentenced to jail time (in the US, this is 6 months or less , however). However, if the key/data is a substantial portion of the prosecution's case, and the sentence you are facing is more than 6 months (or if you are a hardcore civil libertarian type), you may want to tell them to fuck off anyway.