VoIP, Tor and Zfone by Phillip Zimmermann?

Anothony Georgeo anogeorgeo at yahoo.com
Tue May 16 19:20:25 UTC 2006

Good day,

I found some more interesting VoIP links/ideas related
to Tor that are relevent and I thought everyone would
like to read.

--Index of Links:

The first is a proposed study (eg. 'white paper') into
the implications of routing VoIP over Tor...once Tor
is UDP capable that is ;-).  

The second is the previously proposed UDP extension
for Tor (mainly to enable VoIP).  I wish I could code
as to help impliment this feature. 

The third is information about the new cisco VoIP
protocol "Skinny Client Control Protocol" which uses

The fourth is about "SkyPE" which is a VoIP/P2P
program from the creators of KaZaa.  SkyPE is
propriatary with insecure encryption algoryhtm
implamintation and IMHO is not secure or to be

The fith is a link to the Wikipedia article
"Comaparison of VoIP software".


"Evaluating VoIP Performance over the Tor Anonymous
Communications Network (SCISS 2006)"

-Quoted section-

...Routing a VoIP connection through an anonymizing
network can provide privacy but also increases the
latency of the voice connection. In this project we
aim to measure the performance characteristics of VoIP
connections that are sent through a UDP-enabled Tor
network ...

-End quoted section-

"Tor Unreliable Datagram Extension Proposal"

-Quoted section-

0. Introduction

...Tor is a distributed overlay network designed to
anonymize low-latency TCP-based applications.  The
current tor specification supports only TCP-based
traffic.  This limitation prevents the use of tor to
anonymize other important applications, notably voice
over IP software.  This document is a proposal to
extend the tor specification to support UDP traffic...

-End quoted section-

"Skinny Client Control Protocol(SCCP)"

Skinny VoIP protocol (from Cisco) utilizes TCP/IP for
it's *propriatary* :-( VoIP protocol.  

I may be totally misunderstanding what SCCP is/does
but it seems that if a skinny protocol client came
along it may use TCP/IP and thus be routeable through
Tor.  Although, Zfone will be unusable as Zfone uses

"SkyPE VoIP/P2P"

SkyPE is a proprietary peer-to-peer Internet telephony
(VoIP) network that is now owned by E-Bay.

I included SkyPE becuase it has a proxy window which
can route over Socks5/HTTP/S_Proxy/etc.

I would never use SkyPE because I don't trust the

-Quoted from "Comparison of VoIP software-

Twin analyses show that Skype is relatively secure,
uses properly coded algorithms and 1536/2048 bit keys
and 256 bit AES. Some criticism was levelled at the
"black box" nature of the package, the relative short
size of the assymetric keys, and the trust placed in
other computers if they "speak Skype". 

-End quoted section-

"Comparison of VoIP software"


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