Secure Calls

How it Works: Secure, Encrypted Calling with Cellcrypt

Cellcrypt ensures that every voice and video call is protected with military-grade security, designed for high-risk government, military, and enterprise environments.

Here's how Cellcrypt delivers secure calling that goes far beyond traditional VoIP encryption:

1. Call Initiation via SIP – But Smarter

Cellcrypt uses the industry-standard Session Initiation Protocol (SIP) to initiate and manage call sessions. Unlike standard implementations, Cellcrypt enhances SIP signalling by integrating its own secure key management layer. This ensures that sensitive information—like encryption keys—is never exposed, even on trusted servers.

2. Network-Level Encryption with TLS + SRTP

Once the call is set up, two foundational layers of encryption are established:

• TLS (Transport Layer Security): Secures all signalling and control messages.

• SRTP (Secure Real-Time Transport Protocol): Encrypts the audio and video streams for in-transit protection.

These layers ensure that your communications remain safe from passive eavesdropping during transport across the internet or private networks.

3. End-to-End Encryption – Beyond the Server

Cellcrypt doesn't stop at transport-level security. Each call is end-to-end encrypted, meaning:

• Encryption keys are generated and stored only on the caller’s and recipient’s devices.

• Media content is encrypted before leaving the device and decrypted only upon arrival.

• No plaintext audio, video, or keys are ever passed through or stored on Cellcrypt servers.

  
  

This architecture neutralises threats like Man-in-the-Middle (MiTM) attacks—even if the network or server is compromised.

4. Post-Quantum Protection

To defend against future quantum computing threats, Cellcrypt integrates Post-Quantum Cryptography (PQC) into its encryption stack. This safeguards call data not only today, but decades into the future, against "harvest now, decrypt later" threats.

5. Session-Specific Keys and Perfect Forward Secrecy

For every call, Cellcrypt generates a unique, ephemeral session key:

• Ensures Perfect Forward Secrecy (PFS)—past calls remain secure even if long-term keys are compromised.

• Keys are never reused or stored outside of the endpoints.

6. User-Level Authentication & MiTM Detection

During a call, each user sees a 6-digit session code derived from the encryption keys. Users can:

• Verify this code verbally to confirm both ends are truly connected without interference.

• Immediately detect a MiTM attack, as session codes will differ if an attacker is intercepting the call.

7. Secure Call Bridging and SIP Interoperability

Need to connect to external SIP devices or desk phones? Cellcrypt’s secure SIP gateway ensures interoperability:

• Internal calls between Cellcrypt devices are fully encrypted end-to-end.

• External SIP connections are protected via SRTP, but end-to-end security cannot be guaranteed unless both parties use Cellcrypt.

Why It Matters

Traditional VoIP solutions trust the network and server. Cellcrypt doesn’t. Our Zero-Trust architecture is built to assume compromise and still protect your communications.

From battlefield briefings to boardroom strategy, when a call must remain private, Cellcrypt delivers absolute confidentiality. Cellcrypt's cutting-edge voice call encryption codecs ensure high-definition call quality, optimising data and battery usage even across the most austere, low-bandwidth mobile and wireless networks.

With Cellcrypt, flexibility is at the forefront. Our platform supports secure calling over a wide range of IP-based networks, including 5G, 4G/LTE, 3G/HSDPA, Wi-Fi, and satellite networks.

Moreover, we prioritise the mutual authentication of all call participants to eliminate any potential risks associated with Caller ID spoofing and man-in-the-middle (MiTM) attacks.

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Designed for government, defence, and enterprise use, Cellcrypt Secure Calls ensure that your most critical conversations are always protected.