Types of Dark nets

 Friend to Friend Type (or F2F)
 Is a type of peer-to-peer network in which users only make direct connections with people they know. Passwords or digital signatures can be used for authentication.(usually used for file sharing with a peer-to-peer connection).

Privacy 
It is a network type which consider the personal privacy Information such as Tor concerning the storing,Privacy can involve either Personally Identifying Information (PII)  or non- Personally Identifying information such as a site visitor's behavior on a website. PII refers to any information that can be used to identify an individual. For example, age and physical address.