Features

• Instant messengers show an interactive, typed conversation between two or more people. Each entry is visible by all participants. IM systems also include the feature to save a conversation. This may present a problem for anyone who has betrayed a secret or written something libelous. The OTR system enables anyone to alter or insert statements after a conversation has terminated. There is also no participant digital signature to identify the source of a statement. This makes it impossible to prove the source of a statement.
  
  

Function

• The regular security features of OTR include authentication via the Diffie-Hellman method of a "shared secret." Authentication occurs after key exchange. This process is called the Authenticated Key Exchange.
  
  

Services

• OTR also fragments statements for transmission where a message exceeds the network's maximum message size. Regular key exchanges mean that forwarded messages do not compromise security for later conversations. This is called "perfect forward secrecy."