Portraits connected through a network of lines. Key icons sit next to each person.

Our users own the keys

Silent Circle is the world leader in end-to-end encryption and authentication. Your calls and messages never leave your device unencrypted. Your private keys never leave your device at all. No one but your intended recipient can decrypt your traffic, not even us.

Learn more about Silent Phone
Two portraits enclosed in a circle. An illustration of a spy sits outside the circle.

Keep out the man-in-the-middle

Our unique Security Words put you in control of your own security. The words are computed independently on each device. If they match, you can be absolutely certain no one is listening in.

Learn more about Security Words

Trusted by companies and government agencies around the world

  • A lock icon with circuit lines.

    Privacy-first platform

    If you're not paying for an app, you and your data might be the product really being sold. At Silent Circle, we keep things simple. Our customers are our customers. Our product is ensuring privacy.

  • A door with a lock icon.

    No backdoors

    The software you run should serve only you. We build products that keep out those who would do you harm. We'll never open that door. Our products have no backdoors.

  • Pages with a magnifying glass.

    Peer reviewed

    Our core cryptographic protocols have been published and have stood the test of time. Some are standards that have been published by the IETF.

Built on a fundamentally different protocol

Silent Phone calls among your team members are secured using ZRTP. The protocol was developed by Silent Circle founder Phil Zimmermann. The standard was published by the IETF in 2011. It's widely recognized as the most secure telephony standard ever developed. With Silent Phone, you can talk with someone a continent away as securely as if you were standing in the same room.

  • Pure peer-to-peer key agreement
  • Perfect forward secrecy
  • Protection against MITM attacks
  • Enterprise-grade 256-bit security level
  • Key continuity and post-quantum resistance
  • Security without a PKI
  • The best call quality in the business

No logging

We don't log the history of calls or messages between users. Most companies log and store everything "just in case." We know that no good comes from keeping more data than is absolutely needed. Data not stored can never be lost or compromised. Your company's data is yours. We don't want to hold any more of it than we need.


We keep things simple. Your data is your own. We never see the content of your conversations. We never touch your private keys. Our software works for you and only you.

Read our privacy policy
Philip R. Zimmermann
At Silent Circle we've come to realize that protecting individuals at work may be the strongest form of corporate security possible.

Phil Zimmermann

Founder of Silent Circle and creator of Pretty Good Privacy (PGP)

Let our technology help you protect your team's communications