[Asterisk-Users] Encryption

[Brian West]

I understand AES can do this.

bkw

On Thu, 25 Dec 2003, Steve Underwood wrote:

> Steven Critchfield wrote:
>
> >On Wed, 2003-12-24 at 19:11, Mahoney, Matt wrote:
> >
> >
> >>Hi,
> >>
> >>
> >>Does asterisk support any kind of voice encryption?
> >>
> >>
> >
> >Not right now. As I understand it, it is a problem with the fact that
> >each packet would have to be able to be decrypted even if packets in the
> >stream are lost. In the long run it is going to be a question of how
> >secure do you need it to be. Afaik, the good encryption methods are
> >stream based, and the loss of packets would kill the decryption.
> >
> >Add to that the problem of finding some encryption method that can deal
> >with small packets without adding a lot of overhead. Each voice packet
> >in IAX with GSM compression isn't very long. The voice data is only 33
> >bytes.
> >
> >
> The need to tolerate packet losss means a continuous stream cypher can't
> be used. That reduces the quality of the ciphering, but it can still be
> pretty good. You know the packet sequence number (at least with RTP you
> do), so some forms of sequentially changing encryption can still be
> used. SRTP has been through the process of trying to deal with this in
> the most effective manner, but doesn't seem to be widely used right now.
> Free implementations exists - see srtp.sourceforge.net. I guess it
> should be adaptable to IAX.
>
> Regards,
> Steve
>
>
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