otr_parse(1) User Commands otr_parse(1)NAME
otr_parse, otr_sesskeys, otr_mackey, otr_readforge, otr_modify,
otr_remac - process Off-the-Record Messaging transcripts
SYNOPSISotr_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 flags snd_keyd rcv_keyd 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 conversa‐
tion 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 not be forged with‐
out real-time access to the secret keys on the participants' computers,
and in that case, all security has already been lost.] Easily-forge‐
able transcripts help us provide the "Deniability" property: if someone
claims you said something over OTR, they will 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.
EXTENDED DESCRIPTION
The following commands are supported:
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 do not 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 flags snd_keyid rcv_keyid pubkey counter encdata
revealed_mackeys
Make a new OTR Data Message, with the given pieces (note that the
data part is already encrypted). MAC it with the given mackey.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │communication/im/pidgin │
├─────────────────────────────┼─────────────────────────────┤
│Interface stability │Volatile │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOpidgin(1), attributes(5)
Off-the-Record Messaging, at http://www.cypherpunks.ca/otr/
NOTES
Written by the OTR Dev team (otr@cypherpunks.ca). Updated by Brian
Cameron, Sun Microsystems Inc., 2007.
SunOS 5.11 13 Nov 2007 otr_parse(1)
