Here's an idea I've been playing around with that I thought I would mention. There's a concept project out of MIT (http://css.csail.mit.edu/cryptdb/ called CryptDB) that allows database operations to be performed on encrypted data. This is perfect for a darknet market. From its webpage: "CryptDB is a system that provides practical and provable confidentiality in the face of these attacks for applications backed by SQL databases. It works by executing SQL queries over encrypted data using a collection of efficient SQL-aware encryption schemes. CryptDB can also chain encryption keys to user passwords, so that a data item can be decrypted only by using the password of one of the users with access to that data. "
This is exactly the kind of thing that a darknet market could really use. There would be no danger of compromise even if the servers were seized because all the operations necessary could be performed on encrypted data. Buyer and seller could have a shared key that is chain encrypted with their passwords for sharing address/order info.
Thoughts?
The NSA made them include a backdoor.