Secure telephones

Dave Howe DaveHowe at
Sun Jul 18 12:53:35 PDT 2004

Jack Lloyd wrote:
> How well is VoIP going to work over SSL/TLS (ie, TCP) though? 
you can do SSL over UDP if you like - I think most VPN software is UDP 
only, while OpenVPN has a "fallback" TCP mode for cases where you can't 
use UDP (and TBH there aren't many)

 > I've never used
> any VoIP-over-TCP software before, but some people I know who have say it sucks
> (terrible latency, sometimes as bad as 5-10 seconds). 
PGPfone had that problem, even over landlines (no IP involved) - 
however, I think that was more do to with the compression codecs and the 
crypto than any external problems, as switching to half-duplex usually 
cleared the problems up.

> That may have just been
> an artifact of a bad implementation, though. DTLS might be a better pick for
> securing VoIP. There's also SRTP.
The strength of a pure VPN solution is that you aren't limited to *just* 
VoIP - you can transfer files, use whiteboarding, run videoconferencing, 
support text channels..... even play games :)

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