Secure VOIP calls

Phil Zimmermann is a living legend – a cryptographer he released a cryptographic program PGP for the encryption of email and files on computers as open source freeware in 1991. Zimmermann was pursued through the courts by the US Customs in a criminal investigation for exporting cryptographic software in breach of US export regulations. The case was eventually dropped by the government without indictment in early 1996. In the meantime PGP encryption software has helped countless organisations communicate safely.

Now, Phil has released an open source Beta of his new product – Zfone – a product to secure voip calls. As Phil himself says:

I think it’s better than the other approaches to secure VoIP, because it achieves security without reliance on a PKI, key certification, trust models, certificate authorities, or key management complexity that bedevils the email encryption world. It also does not rely on SIP signaling for the key management, and in fact does not rely on any servers at all. It performs its key agreements and key management in a purely peer-to-peer manner over the RTP packet stream. It interoperates with any standard SIP phone, but naturally only encrypts the call if you are calling another Zfone client. This new protocol has been submitted to the IETF as a proposal for a public standard, to enable interoperability of SIP endpoints from different vendors.

To use Zfone you need to have an already working SIP compliant VOIP softphone like X-Lite,
Gizmo, or SJphone. The current beta is only released for Linux or Mac with the Windows version due in mid-April.

I have downloaded a copy and would love to try it out so if anyone else gets a copy and would also like to try it – my Gizmo username is tomraftery

3 thoughts on “Secure VOIP calls”

  1. Incredible. I love how he prevents against middle-man attacks by simply having the users call out and compare their authentication codes. Very clever and so straight-forward.

  2. Hea T,

    Righto..we have a date tonight then 😉


    The only problem is that it uses softphones…no hardware phones (yet)


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