Standards Documentation¶

Open {Secure,Source,Standards} Telephony Network (OSTN)

We are working to define a defacto standard by which a voice over internet protocol service can be considered end-to-end secured, with verifiable encryption, minimal logging, and a decentralised model of deployment and use. From this standard, we will work to deploy a network of compliant server/service instances and client software, mobile and desktop, that are federated, audited and interoperable.

Summary¶

All of the necessary technologies and communications standards exist today for voice communications that is as secure as OpenPGP email. Many proprietary and open source solutions exist for desktop and mobile devices that already implement the necessary bits to provide a solution many times more secure than Skype, without dependence upon one global service provider. Yet people who are security conscious enough to use Skype to secure their computer based conversations will still hold sensitive discussion on mobile phones. The problem is simplicity, usability and reliability.

This project will provide an application for Android phones that will be only marginally more complex to use than dialing an existing phone number, while still being based entirely on open standards. The app itself is based on existing open source client code provided by the CSipSimple, pjsip and ZORG projects. We will coordinate with a network of audited, open service providers around the world who already provide free and commercial service to users, to ensure our users have an automated provisioning process to get connected.

OSTN will interface with a variety of projects to ensure compatible with new standards around peer-to-peer VOIP communication. We will seek interoperability from other competitive, proprietary solutions from private companies and propose our implementation become the reference design for privacy and security standards.

This project would not exist without the support of our good friends at Tanstagi http://tanstagi.net and Freeborn.Devio.us http://freeborn.devio.us/doku.php?id=freeswitchfreebsd

Compliance Specification¶

• MUST require verifiable encryption of all signaling data

• SHOULD utilize SSLv2/3 for the SIP signaling channel
• SHOULD utilize a Root Certificate Authority that has a trusted status

• MUST allow encryption of Real-time Transport Protocol (RTP) media stream

• MUST support proxying of media streams
• MUST support unmodified proxying of ZRTP encrypted
• MUST support voice calling
• MAY support video calling

• MUST run in as secured server environment as possible

• SHOULD utilize full disk encryption
• SHOULD run on a locked down instance of a known secure operating system
• SHOULD utilize an intrusion detection capability

• MUST provide either simple extensions or friendly name user identifiers

• MAY support use of existing device telephone numbers as identifiers
• MAY support use of existing handles/usernames as identifier and callerid

• MUST operate in a privacy preserving manner towards user data

• MUST NOT require real name or other personally identifying information
• MUST anonymous or remove all system logs, and only use logs for diagnostics
• MUST notify the user when the server is compromised or otherwise put into a state that could cause them risk or harm

• MAY provide additional telephony services, so long as they are not privacy reducing

• MAY provide voicemail service, though it should be stored in an encrypted manner
• MAY provide SIP-based messaging through it should be done via the OTR protocol