Project overview.

Back in the time when mobile messaging apps stored messages in plain text and calls could be eavesdropped we were approached by a revolutionary American based startup who believed that messaging and VOIP calling should be secure, and that such security should be publicly provable not just declarable.

During our cooperation we have delivered and maintained a secure VOIP calling and messaging mobile app integrating a Latvian made VOIP engine.

With Silent phone we had the unique chance to collaborate with the inventor of ZRTP Phil Zimmerman and pioneer the Diffie-Hellman algorithm with SAS verification.

App functionality:

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1)Encrypted VOIP calls with SAS verification. One of the first apps to implement encrypted video calls
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2)End to end encrypted serverless group chats
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3)Encrypted voice, video, messaging and file sharing

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4)Private communication with landline numbers anywhere in the world

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5)One of the first apps to implement secure message deletion for all conversation participants

Solution

By analysing the product we understood that we have to create a UI that is friendly for the users, since the security/encryption part might be very fustraiting for the average person.

Our proposed UI is following general Apple and other messeging UI guidelines in order to make usability similar to other messaging/calling apps, but with security elements in mind.

Helping to take the Silent phone app to customers we made a clean mobile UI, integrated and maintained the Tivi VOIP engine along with our own forks of zrtp, and message encryption libraries.

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