Tor Browser
Also known as the Onion Router, Tor is a specially designed Internet routing system that routes traffic while encrypting the IP address of where it came from. To enable routing, only the last and next IP addresses are available at each hop. The original and all other hops along the way are encrypted and can only be decrypted by a Tor router. You can access the Tor network by using the Tor browser, which is simply a plug-in to the open-source browser, Firefox.
Proxies
A proxy server acts as a gateway between you and the internet. It’s an intermediary server separating end users from the websites they browse. Proxy servers provide varying levels of functionality, security, and privacy depending on your use case and needs. Internet traffic flows through the proxy server on its way to the address you requested. The request then comes back through that same proxy server and then the proxy server forwards the data received from the website to you. Using proxies is a tried and true method of obscuring your identity on the Internet. Although your traffic is not encrypted and can be sniffed, the traffic cannot be attributed to any person as the proxies use their IP addresses rather than yours. However, this does not prohibit your traffic being tracked by your cookies.
VPN
Short for a virtual private network, a VPN, is a private way to connect over a public network to a private network. It requires an authentication mechanism and then encrypts all the traffic between the client-to-server or peer-to-peer communication. It can encrypt all communication including the control channels, making it very hard to crack or identify the user. You can access private VPN services where you will connect to their VPN server through an encrypted tunnel and then browse the Internet with their IP address. All of your traffic appears to be from their IP address and your communication to the service is encrypted so the traffic can not be traced back to you. See Also: How to use Opera’s new VPN for Android
Encrypted P2P Chat or Encrypted VoIP
These methods make it easy to chat or use voice communications over the Internet securely. These technologies encrypt voice and chat communications that make it very difficult to intercept and read. Chatting platforms like Whatsapp and Telegram are secured by end-to-end encryption. For VoIP, consider ZRTP for private voice communication. ZRTP, which is composed of Z and Real-time Transport Protocol, is a cryptographic key-agreement protocol to negotiate the keys for encryption between two endpoints in a Voice over Internet Protocol (VoIP) phone telephony call based on the Real-time Transport Protocol. For those of you not familiar with cryptography and password-cracking, salting makes it more difficult for a third-party to break the encryption.
A Word of Caution
You need to be very careful when using any commercial product for purposes of maintaining anonymity. The reason is that these companies easily bow to pressure from anyone with authority or power to enable snooping on their networks and products. Although not perfect, open-source products are more likely to give you a greater level of assurance for maintaining your anonymity and privacy.