Tag: zrtp

SIP Dialog

VoIP security architecture in brief

Voice over IP (VoIP) has been around for a long time. It’s ubiquitous in homes, data centers and carrier networks. Despite this ubiquity, security is rarely a priority. With the combination of a handful of important standard protocols, it is possible to make untappable end to end encryption for an established VoIP call. TLS is the security protocol between the…

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Whit Diffie

Threats and Usability of Secure Voice

In my previous post I found that end-to-end encryption with OSTN is both effective and usable. There are two important things the user must be aware of when using OSTN. They must confirm with each phone call that the encryption icon is present and  they must correctly complete SAS verification dialog boxes. So on a basic level, encrypted voice just…

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A Network Analysis of Encrypted Voice over OSTN

Introduction to OSTN The OSTN network stands for Open Source Telephony Network. It is a federated network standard for supporting Internet calling with end-to-end encryption ala ZRTP. Its very similar to e-mail in that VOIP calls can be routed to addresses such as user@domain.tld. Its a simple concept, but I believe it to be ground breaking implementation! Never before have…

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Build your own Open Secure Telephony Network, some assembly required

The Open Secure Telephony Network is a standard that defines how to configure a VoIP softswitch with the capability to have secure two-way VoIP conversations if both parties are using the same server. The system requires both backend and frontend components, which makes OSTN is a little different than some of the other Guardian apps. Unlike Gibberbot, there are few…

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