The Importance of Secure Multimedia Sessions in Microsoft Teams Telephony

Modern businesses rely heavily on unified communication platforms to stay connected, collaborate efficiently, and serve customers across geographies. As organisations increasingly depend on voice, video, and screen-sharing tools for daily operations, securing these digital interactions has become essential. Microsoft Teams Telephony provides a comprehensive solution that combines seamless collaboration with strong, built-in security for every session.

When a company handles confidential information—client data, financial transactions, intellectual property, or internal discussions—it must ensure those conversations remain private and protected. Microsoft Teams Telephony strengthens this trust by implementing advanced encryption, authentication, and compliance measures that safeguard multimedia sessions from start to finish.

Securing Multimedia Sessions in Microsoft Teams Telephony

Microsoft Teams Telephony protects communication through a combination of encryption, identity management, network optimisation, and regulatory compliance.

1. Encryption Protocols and End-to-End Encryption

Microsoft Teams supports end-to-end encryption (E2EE) for one-to-one voice and video calls. With E2EE enabled, calls are encrypted at the sender’s device and decrypted only at the receiver’s device, ensuring that no intermediary can access the content.

Encryption keys are established through Datagram Transport Layer Security (DTLS) using per-call certificates on each endpoint. This process remains hidden even from Microsoft, adding an extra layer of privacy. To verify secure connections, both participants can compare a unique 20-digit security code generated from the SHA-256 thumbprints of their call certificates, confirming there is no interception or tampering.

All Teams media traffic—calls, meetings, and screen shares—is encrypted using Secure Real-time Transport Protocol (SRTP). SRTP ensures confidentiality, authentication, and protection against replay attacks, while session keys are exchanged securely via a TLS-protected channel.

Teams data at rest is also encrypted. Businesses can manage their own encryption keys through Microsoft 365’s Customer Key feature, allowing greater control over data protection.

2. Secure Signalling

To protect signalling traffic, Teams uses TLS 1.2 and AES-256 encryption. These protocols secure call setup, teardown, and session management messages, preventing interference or manipulation during communication.

Identity and Access Management

Strong identity verification ensures that only authorised users access Teams sessions. Microsoft Teams integrates with Azure Active Directory (Azure AD) for authentication and access control.

• Multi-Factor Authentication (MFA): Adds another verification layer, reducing unauthorised access.
• Conditional Access Policies: Enforce restrictions based on device status, location, and user risk.
• Credential Tokens: Teams uses credential-based tokens exchanged via TLS-secured channels when peer-to-peer connections are not possible.
• Role-Based Access Controls: Define who can initiate, record, or share calls and meetings.

This structure ensures secure access to multimedia sessions while maintaining flexibility for users working across different devices or networks.

Network Optimisation and Security

Microsoft Teams employs advanced network management tools to secure communication while maintaining performance and reliability.

• Session Border Controllers (SBCs): Act as secure gateways that regulate and protect voice traffic, particularly in Direct Routing setups. They prevent eavesdropping, spoofing, and denial-of-service attacks.
• Split Tunnelling: Routes Teams media traffic outside of corporate VPNs to enhance call quality and reduce latency.
• Direct Media Routing: Allows voice and video traffic to travel directly between the SBC and client, bypassing unnecessary cloud relays while maintaining encryption.
• Dynamic Quality Adjustment: Teams automatically adjusts video and audio quality based on available bandwidth, ensuring uninterrupted conversations.

Compliance and Regulatory Controls

Microsoft Teams Telephony is built to meet the needs of industries with strict data protection requirements. It supports compliance with frameworks such as HIPAA, GDPR, and ISO/IEC 27001.

Key compliance features include:

• Policy-based call recording and data retention controls.
• Auditing, monitoring, and eDiscovery tools for investigation and record-keeping.
• Data Loss Prevention (DLP) to restrict sensitive data sharing.
• Sensitivity labels to classify and protect communication content.
• Integration with Compliance Manager to help organisations evaluate regulatory adherence.

These measures allow businesses to operate within legal boundaries while maintaining transparency and accountability.

Data Protection in Transit and at Rest

Microsoft Teams ensures all communication data—including messages, media, and shared files—is encrypted during transmission and storage. Even if intercepted, this data remains unreadable without proper decryption credentials. Access control policies restrict unauthorised users, ensuring complete data integrity.

Best Practices for Maintaining Secure Multimedia Sessions

To maintain the highest level of protection, organisations should implement the following practices:

• Enable Multi-Factor Authentication and Conditional Access for every user.
• Use certified Session Border Controllers configured for TLS and SRTP.
• Activate End-to-End Encryption for one-to-one calls involving sensitive data.
• Apply strict device and identity governance policies.
• Conduct regular audits of call logs and compliance configurations.
• Educate users on secure communication habits and data handling.

Use Cases for Secure Multimedia Sessions

1. Healthcare: Hospitals and clinics rely on Teams Telephony for telemedicine consultations that require strict HIPAA compliance. End-to-end encryption ensures that patient data remains private during voice and video sessions.
2. Financial Services: Banks and investment firms use Teams to communicate securely with clients. Features such as policy-based call recording, SRTP/TLS encryption, and Data Loss Prevention ensure compliance and protect sensitive financial information.
3. Government and Public Administration: Government departments use Teams for both internal collaboration and public-facing services. Conditional Access, Defender for Endpoint integration, and encrypted sessions help maintain confidentiality in high-security environments.

Why Choose Viva’s Microsoft Teams Telephony

Viva’s Microsoft-certified Teams Telephony (VTC) solution is designed to deliver reliable, secure, and high-quality multimedia communication. It supports virtual meetings, live webinars, training sessions, and one-on-one calls—all safeguarded by advanced encryption and compliance mechanisms.

With built-in Session Border Controllers, Viva ensures that every connection between users, departments, or external participants remains protected while maintaining smooth performance and minimal latency.

Whether your business manages sensitive financial data, patient records, or confidential corporate discussions, Viva Teams Telephony provides the assurance of secure communication at every step.

To learn more or schedule a live demonstration, contact our team today.