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Updated: Thursday, June 13, 2019
 
 

otr_toolkit (1)

Name

otr_toolkit - otr_parse, otr_sesskeys, otr_mackey, otr_readforge, otr_modify, Record Messaging transcripts

Synopsis

otr_parse
otr_sesskeys our_privkey their_pubkey
otr_mackey aes_enc_key
otr_readforge aes_enc_key [newmsg]
otr_modify mackey old_text new_text offset
otr_remac  mackey  sender_instance  receiver_instance  flags  snd_keyid
rcv_keyid pubkey counter encdata revealed_mackeys

Description

OTR_PARSE(1)                General Commands Manual               OTR_PARSE(1)



NAME
       otr_parse,   otr_sesskeys,   otr_mackey,   otr_readforge,   otr_modify,
       otr_remac - Process Off-the-Record Messaging transcripts

SYNOPSIS
       otr_parse
       otr_sesskeys our_privkey their_pubkey
       otr_mackey aes_enc_key
       otr_readforge aes_enc_key [newmsg]
       otr_modify mackey old_text new_text offset
       otr_remac  mackey  sender_instance  receiver_instance  flags  snd_keyid
       rcv_keyid pubkey counter encdata revealed_mackeys

DESCRIPTION
       Off-the-Record (OTR) Messaging allows you to have private conversations
       over IM by providing:
        - Encryption
          - No one else can read your instant messages.
        - Authentication
          - You are assured the correspondent is who 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
          - If you lose control of your private keys, no previous conversation
            is compromised.

       The OTR Toolkit is useful for analyzing and/or  forging  OTR  messages.
       Why  do  we  offer this?  Primarily, to make absolutely sure that tran-
       scripts of OTR conversations are really easy to forge after  the  fact.
       [Note that during an OTR conversation, messages can't be forged without
       real-time access to the secret keys on the participants' computers, and
       in  that  case,  all security has already been lost.]  Easily-forgeable
       transcripts help us provide  the  "Deniability"  property:  if  someone
       claims you said something over OTR, they'll have no proof, as anyone at
       all can modify a transcript to make it  say  whatever  they  like,  and
       still have all the verification come out correctly.

       Here are the six programs in the toolkit:

        - otr_parse
          - Parse OTR messages given on stdin, showing the values of all the
            fields in OTR protocol messages.

        - otr_sesskeys our_privkey their_pubkey
          - Shows our public key, the session id, two AES and two MAC keys
            derived  from the given Diffie-Hellman keys (one private, one pub-
       lic).

        - otr_mackey aes_enc_key
          - Shows the MAC key derived from the given AES key.

        - otr_readforge aes_enc_key [newmsg]
          - Decrypts an OTR Data message using the given AES key, and displays
            the message.
          - If newmsg is given, replace the message with that one, encrypt
            and MAC it properly, and output the resulting OTR Data Message.
            This works even if the given key was not correct for the original
            message, so as to enable complete forgeries.

        - otr_modify mackey old_text new_text offset
          - Even if you can't read the data because you don't know either
            the AES key or the Diffie-Hellman private key, but you can make a
            good guess that the substring "old_text" appears at the given
            offset in the message, replace the old_text with the new_text
            (which must be of the same length), recalculate the MAC with the
            given mackey, and output the resulting Data message.
          - Note that, even if you don't know any text in an existing message,
            you can still forge messages of your choice using the
            otr_readforge command, above.

        - otr_remac mackey sender_instance receiver_instance  flags  snd_keyid
       rcv_keyid pubkey counter encdata revealed_mackeys
          - Make a new OTR protocol version 3 Data Message, with the given
            pieces (note that the data part is already encrypted).  MAC it
            with the given mackey.



ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       +---------------+-------------------------+
       |ATTRIBUTE TYPE |    ATTRIBUTE VALUE      |
       +---------------+-------------------------+
       |Availability   | communication/im/libotr |
       +---------------+-------------------------+
       |Stability      | Uncommitted             |
       +---------------+-------------------------+
SEE ALSO
       Off-the-Record     Messaging,     at    https://www.cypherpunks.ca/otr/
       <https://www.cypherpunks.ca/otr/>

AUTHOR
       otr_toolkit was written by the OTR Dev Team <otr@cypherpunks.ca>.



NOTES
       This    software    was    built    from    source     available     at
       https://github.com/oracle/solaris-userland.    The  original  community
       source       was       downloaded       from        https://otr.cypher-
       punks.ca/libotr-4.1.1.tar.gz

       Further information about this software can be found on the open source
       community website at https://otr.cypherpunks.ca/.



                                March 14, 2012                    OTR_PARSE(1)