Can anyone eavesdrop my VoIP call?

May 13th, 2008 by Cesar Herrero

VoIP networks use the real time protocol (RTP) to send voice over the Internet. Although RTP chunks, encodes and packetizes audio in a simple but efficient way, it has no consideration for security and data integrity.

In fact the lack of security makes RTP (and VoIP in general) a target of call “wiretapping”. How is this possible, you may ask? Well folks, read this below to try it yourself!

  1. Download and Install wireshark (http://www.wireshark.org)
  2. Run Wireshark and start capturing packets with the appropriate NIC
  3. Place a G.711 mu law call using Kapanga
  4. On Wireshark, stop capturing packets
  5. Run statistics/RTP/Show all streams
  6. Click on the streams in the list, do a stream analysis and save the payload as an audio file
  7. Congrats: you have a recording of the call (one stream per direction)

How can we prevent this from happening? SRTP is an upgrade to RTP that provides security through encryption and authentication. Encryption specifically guarantees that the audio is unintelligible by the time it is sent out. So if we go back to item #3 on the list above we place an SRTP call instead, the recorded audio will sound like “noise”, this is because SRTP rearranges information in the payload using the AES algorithm.

So how’s your softphone’s SRTP support? As it turns out we spent quite a bit of time supporting this feature. And yes, it is available in the public site. Enjoy!

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How does an Internet Telephony Provider works?
In Search of Quality of Service Testing, Part I

Video Surveillance, the Kapanga Way…

September 16th, 2007 by Martin Cadirola

Next time you go on vacation you may want to consider Kapanga as a cheap, reliable and effective way to video-monitor your house (or office) activity. Some members of the Kapanga team use it to ensure the pet sitter is taking good care of your pets while you are out :>)

So how does Kapanga work as a video surveillance device? Here are the main requirements:

1. Multiple Kapanga Softphones are distributed in the area to be monitored.
2. Each Kapanga may be connected to multiple cameras.
3. Kapanga Softphones can talk to other Kapanga Softphones and access each other video feeds and control information.
4. Kapanga Softphone can detect motion, loud noises, temperature changes and other trigger actions/alarms.

While you are out, you can call home from your 3G phone and a Kapanga Softphone will automatically answer. After entering a Username and Password the Kapanga will give you access to the video feed of all the cameras. Your home-based Kapanga will also provide control and status information of all the detectors since your last call. Sounds like 007 stuff, eh?

Another cool thing you can do is to configure Kapanga to call you in case of any event triggered (for example an alarm triggered by an event). We used this setup at a NASA group during a scientific field campaign when an instrument needed on-site attention at random times. We configured Kapanga to call one of our engineers’ cellphone when attention was required. And voilá!

If you want to give this feature a try, please feel free to contact us at support [at] kapanga [dot] net.

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In Search of Quality of Service Testing, Part I
Troubleshooting VoIP: What is Dead Air?
Contributors

Skype down…SIP up?

August 16th, 2007 by Martin Cadirola

This morning I learned that Skype has been down due to a “software failure” leaving millions of people unable to use it. I know lots of people use Skype for their personal and business use. I won’t be celebrating this problem even though they are an indirect competitor. What I’m interested in pointing here is that telecom carriers, operators, and service providers will use this glitch to their advantage. My question is how can we ensure that a SIP-based infrastructure can be more reliable than a peer-to-peer framework? All we know is that SIP is here to stay and service providers should be able to ensure reliability from working with far less subscribers than Skype.

For those that want to read more about the Skype glitch, you can read here and here. Oh, and here is an update.

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SIP as a foundation for building modern interactive Value Added Services (Part II)

See you at NXTComm Chicago!

June 18th, 2007 by Martin Cadirola

We’ve been extremely busy with new Kapanga developments so today I’ll be traveling to Chicago to attend the NXTComm trade show. Looks like it’ll be a lot of fun, considering that the IP telephony market has been growing. If you happen to be there and would like to meet me, please send me an email to martin [at] kapanga [dot] net.

Cheers!

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Kapanga spricht Deutsch. Ja wohl!

April 13th, 2007 by Martin Cadirola

In our efforts to support multiple languages (we support English and Spanish), we’re happy to announce the addition of German language to both desktop and mobile versions of Kapanga Softphone. This great work has been done by our kind colleagues in Germany, the Research Group for Telecommunication Networks at the University of Applied Sciences in Frankfurt, Germany. This group works on the future of telecommunication networks with current main focuses on Quality of Service (QoS) and value added services in IP based Next Generation Networks (NGN). For further information please visit their web site.

So how can you do it? Very simple. Just follow this easy steps:

1. Click on the K icon on the upper left side of the phone

2. Select View, then Language and then Deutsch

3. Voilá, you’ve got Kapanga now working in German

Enjoy!

PS: If you are a big fan of Kapanga and you are interested in translating it to other language, please send us an email to support at kapanga dot net and we’ll work with you on the details. Thanks!Kapanga Softphone adds German language

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