The CSD 3324 SPF secures Group 3 fax communications for mission-critical government, corporate and private applications. The CSD 3324 SPF connects to Group 3 fax machines providing secure fax communications using the AES 256-bit encryption algorithm and Diffie-Hellman public key exchange key management for proven cryptographic strength, and ease of deployment and operation. The CSD 3324 SPF's secure fax encryption features are identical to the CSD 3324 SP secure voice telephone and fax encryption system; therefore, secure fax exchanges are 100% interoperable with the CSD 3324 SP secure fax encryption capability. The CSD 3324 SP also has AES-based secure voice.