February 8, 2008... Internet Wiretap Exposure.

"Voice over IP is more vulnerable to interception than the public switched telephone network." - Phil Zimmermann

Zimmermann is the well known creator of PGP (encryption software), and his recent ZPhone project (for encrypting SIP based VOIP calls) is widely applauded in the small but technically skilled SIP development community. His comments about the vulnerability of VOIP to wiretap are terribly important and those who fail to heed the warning do so at their peril.

It seems quite likely that ZPhone will turn out to be the encryption leader for SIP based voice-over-IP traffic, which is presently (and in my view indefinitely) far less popular and capable than Skype. Skype's encryption, although probably less robust than ZPhone (a software add-on in most cases), has nevertheless a distinct advantage in that it has a single encrypted envelope through which all the forms of communication (voice, video, file transfer, and chat) flow. There is no guesswork as to whether encryption is turned on because it is automatic (in Skype-to-Skype connections). Indeed, encryption enabled privacy is completely invisible in Skype. There is zero slowdown as a result of it, and unlike ZPhone, there is zero configuration. It's just there.