Support encryption in Android IAX2

Question

Can you add encryption for IAX in android?

Answer 1

At this time we have no plans to add encryption to iax2, the RFC does not contain information on how to do it.

Comments

https://tools.ietf.org/html/rfc5456#section-7.4

The RFC does have information on encryption on how to do encryption.  I would like to see this implemented.

"7.4. Encryption

   IAX supports call encryption using the symmetric key, Rijndael [AES]
   block cipher (also called AES -- Advanced Encryption Standard).
   Rijndael is a 128-bit block cipher utilizing a shared secret.  IAX
   encrypts on a call-by-call basis starting with a plaintext NEW
   message indicating, in addition to the other message parameters, that
   the call should be encrypted.  This indication is given by sending
   the ENCRYPTION IE (Section 8.6.34) in the NEW request message.  If
   the called host supports encryption, it will respond with a plaintext
   AUTHREQ message that also includes the ENCRYPTION IE.  All subsequent
   messages in the call MUST be encrypted.  If the called host does not
   support encryption, the AUTHREQ sent in response to the NEW must not
   include the ENCRYPTION IE and the calling host MUST either HANGUP the
   request or continue with the unencrypted call.

   The key to use in encrypting the messages is computed by taking the
   CHALLENGE IE Section 8.6.14 from the AUTHREQ and concatenating any
   one of the shared passwords then computing the 128-bit MD5 digest of
   this combination.  To decrypt, if there is more than one password for
   the peer, each must be tried until the message is successfully
   decoded.  The key remains constant for the duration of the call.
   Only the data portion of the messages are encoded."