Silent Circle

Silent Circle is a mobile security company that develops encrypted communications products for enterprise and consumer markets. Its core offerings center on secure voice calls, messaging, and mobile device solutions designed to protect communications from interception, surveillance, and data exfiltration. The company is known for Silent Phone, a secure calling and messaging application available on iOS and Android, which provides end-to-end encrypted voice and text communications. Silent Circle also developed the Blackphone, a privacy-focused Android smartphone running PrivatOS, a hardened version of Android built to minimize attack surface and protect user data. The Blackphone was developed under SGP Technologies, a joint venture associated with Silent Circle. Silent Circle targets enterprise customers, government agencies, and security-conscious individuals who require protection against threats such as cellular interception (including SS7 vulnerabilities), man-in-the-middle attacks on Wi-Fi networks, and nation-state surveillance. The company positions its products for use cases including BYOD (Bring Your Own Device) enterprise deployments, international travel, and regulated industries requiring secure communications. The platform includes a management dashboard for enterprise administrators, enabling centralized control over secure communications deployments. Silent Circle has also published guidance on mobile security best practices, covering topics such as VPN usage, mobile device management (MDM), and risks associated with unsecured networks and foreign cellular infrastructure.