For years, “data diode” has meant one thing: a one‑way link you can trust. Data flows out, nothing comes back in. That simple guarantee underpinned one‑way security and audit‑ready compliance for the world’s most critical systems. But today, mission and operational demands need more than a simple one‑way pipe.

Protocol Filtering Diodes (PFDs) are the next step. A PFD extends a hardware‑enforced, unidirectional diode with FPGA‑based protocol filtering, providing additional security by enforcing protocol rules on data flows to protect high-security, cannot-fail systems from backchannel threats.

From “Just One Way” to “One Way and Aware”

Previous generations of data diodes deliver deterministic, physical separation through the laws of physics: information moves one way, and there is no return path an attacker can exploit. That isolation is still essential for critical systems where uptime and safety are non‑negotiable but modern environments depend on complex protocols and structured data formats. A simple one‑way link cannot tell you:

Whether traffic really matches the allowed protocol it is supposed to use (and is not some other protocol trying to tunnel through).

Whether protocol messages are well‑formed and conform to allowed protocol behaviors and parameters.

Whether a given protocol operation or message type is permitted to cross the boundary at all, according to the configured protocol rules.

Protocol Filtering Diodes add this missing intelligence. They combine one‑way hardware enforcement with FPGA-based filtering so you can permit only the specific, mission‑required data flows—and block malformed, unexpected, or malicious traffic at line rate.

Owl Talon™: Hardware‑Enforced Resilience Meets Protocol Filtering

Owl Talon™ PFDs embody this evolution. Owl Talon One™ and Owl Talon Torrent™ are both U.S. Government‑validated Protocol Filtering Diodes that enforce one‑way transfer at up to 1Gbps and 100 Gbps respectively. Owl Talon PFDs empower you to secure high‑risk boundaries without sacrificing performance or operational flexibility.

The Owl Talon One PFD features an all‑in‑one PCIe data diode card that provides up to 1 Gbps unidirectional, protocol‑filtering transfer for OT/ICS, logging, and other moderate‑volume mission use cases. It supports multiple data types on a single device, including TCP, UDP (unicast/multicast/broadcast), NTP, Syslog, SMTP, SNMP traps, RFTS, SFTP, OPC DA/A&E, AVEVA PI Transfer (OPTS), remote screen view, remote desktop, and more.

The Owl Talon Torrent PFD is a next‑generation, high‑speed diode platform engineered for ultra‑demanding sensor, ISR, and bulk data flows. It provides secure, hardware‑enforced one‑way transfer at up to 100 Gbps, with FPGA‑based protocol filtering and support for high‑speed file transfer (RFTS and SFTP) and a high‑speed TCP protocol adapter (TCP‑PA), enabling multiple simultaneous high‑volume data streams on a single solution. It will also support UDP and Syslog data streams, albeit at lower speeds.

Why “Smart” One‑Way Matters Now

Adversaries are increasingly adept at abusing legitimate protocols and hiding attacks inside seemingly normal traffic. Meanwhile, organizations face pressure to modernize, connect OT to cloud analytics, and enable real‑time mission decisions—without downtime or regulatory missteps.

Protocol Filtering Diodes like Owl Talon meet these pressures head‑on:

• They keep your most sensitive systems safely isolated, while enabling the data flows that operations, analytics, and leadership rely on.
• They provide a clear, hardware‑enforced guarantee that boards, regulators, and accreditation authorities can understand and trust.
• They support secure real‑time sharing and speed without trade‑offs, eliminating the false choice between security, performance, and adaptability.

If your one‑way links are not protocol‑aware, they are no longer enough. The next step is a smart, validated Protocol Filtering Diode that delivers resilience, compliance, and mission advantage in a single, hardware‑enforced control.

Learn more about the recent validation Owl Talon Torrent received from the U.S. Government in our latest press release and join our product experts at our upcoming webinar where we’ll discuss additional real-world PFD deployment patterns, OT/IT use cases, and best practices for designing Zero Trust, high‑threat boundaries with Protocol Filtering Diodes.