Devil's Night

My hometown, which is ruled by a big dedicator, everything just happens like what the book 1984 says, people’s conversation has been monitored, not matter in the real world or cyber space of internet. Maybe we can do nothing about the monitoring in real life, but obviously it is not easy to monitor what happen on internet, There is a sophisticated method to bypass this monitoring.

OTR, which is short for Off-the-Record Messaging allow you to have private on conversation over instant message.

It offers you:

Encryption

nobody else can read your message

Authentication

you are promised that the person you are talking to is the right person you think it is

Deniability

The messages you send do not have digital signatures that are checkable by a third party. Anyone can forge messages after a conversation to make them look like they came from you. However, during a conversation, your correspondent is assured the messages he sees are authentic and unmodified.

Perfect Forward Secrecy

Even if your private key is leaked, your previous conversation remains secure.

So how does it work?

Here is a very high level overview

Assume that Alice and Bod try to set up a safe conversation

1. Alice signals to Bob that she would like (using an OTR Query Message) or is willing (using a whitespace-tagged plaintext message) to use OTR to communicate. Either mechanism should convey the version(s) of OTR that Alice is willing to use.
2. Bob initiates the authenticated key exchange (AKE) with Alice. Version 2 of OTR uses a variant of the SIGMA protocol as its AKE.
3. Alice and Bob exchange Data Messages to send information to each other.

How to implement this on my computer?

It depends on your operation system and the instant message you use

Here is a compatible list

Windows:
Pidgin (native)
Miranda IM (through plugin)
Trillian (through plugin)
AIM (through proxy)

Linux:
Pidgin (native)
Kopete (through plugin)
Irssi (through plugin)
cLimm (native)
Mcabber (native)
CenterIM (native)

Mac:
Adium (native
AIM (through proxy)
Proteus (through proxy)