Cryptocat

Cryptocat brings encrypted, anonymous chatting to your computer for free. Think of it like a burner for secure instant messaging.

Cryptocat : Secret Question

You can ask a user a secret question in order to confirm his or her identity.

Cryptocat : Sending Files

Crytpocat also lets you send some file types between users.

Cryptocat : Authenicate Users

You have no fixed account in Cryptocat. Furthermore, each line of a chat is encrypted with separate keys.

Cryptocat : Private Message

You can send encrypted messages directly to other users in a conversation.

Cryptocat : Chatting

Cryptocat's approach to messaging is very simple.

Cryptocat : Conversations

Chats on Crytpocat are held in conversations. Most of these don't last, but some persist like the Lobby. Note that Crytpocat merely encrypts your messages. It can't protect you from suspicious characters.