Quside at DEF CON 2025: Showcasing the Future of Trusted Randomness

This year, Quside was honored to join DEF CON  33 Quantum Village, where we presented our quantum technologies and their role in building more secure digital systems. Over four days, our booth became a hub for deep technical conversations about Quantum Random Number Generators (QRNGs) and their unique advantages in entropy reliability, speed, and observability.

Live Demo: QRNG vs. Traditional Entropy

One highlight was a side-by-side demonstration comparing traditional Linux entropy sources with Quside’s high-performance QRNG. Two terminals ran in parallel—one fed by a standard entropy source (e.g. Linux entropy source), the other by our quantum QRNG chip. The results were unambiguous:

• Quside’s QRNG delivered verified entropy (random bytes) at a much higher rate.
• Attendees could see the difference in real time, reinforcing why trusted randomness matters for cryptography.

The demonstration also offered a glimpse into the quantum effects within Quside’s photonic chips, highlighting why this technology stands as one of the most advanced and complete solutions for generating entropy for cryptography. One of the key aspects presented was the ability to verify entropy at the physical level, a cornerstone of Quside’s approach. Attendees could interact with this feature by visualizing PDFs (probability density functions) generated by an actual QRNG. These graphical representations form a central element of Quside’s technology, enabling evaluation of the quantum probabilities behind generating 0s and 1s.

Exploring Quside’s Portfolio

At the booth, participants could also explore Quside’s product portfolio, ranging from 2x2mm photonic chips to high-performance PCIe cards. For those seeking a more playful experience, the “entropy printer” was a highlight: a thermal printer producing unique stickers of quantum random bytes on the spot, allowing visitors to literally take home a piece of quantum randomness.

Keynote Talk: “Faith-Based Cryptography: Running with Unverified Entropy”

One of the most anticipated sessions in Quantum Village was delivered by Quside’s CEO, Carlos Abellán. In his talk, Faith-Based Cryptography: Running with Unverified Entropy, he addressed a challenge that many in cybersecurity quietly acknowledge but rarely confront directly: most of today’s systems still trust randomness they cannot verify.

Carlos explained that cryptography is not only about algorithms—it is about inputs, and the most critical input of all is randomness. Without high-quality entropy, even the strongest algorithms can collapse. He compared it to constructing a skyscraper on unstable ground: no matter how advanced the architecture, if the foundation is weak, the structure is unsafe.

From Research to Real-World Systems

The talk traced Quside’s journey from early research in quantum optics to the creation of scalable, commercial-grade Quantum Random Number Generators (QRNGs). Carlos described how the company’s photonic chips leverage fundamental quantum effects to generate entropy, and why this leap is crucial at a time when systems face both quantum computing threats and the explosive growth of digital infrastructure.

Why “Faith” Isn’t Enough

A key theme of the presentation was the risk of blind trust. Most entropy sources in use today, including hardware RNGs at Level 2 or Level 3, rely on statistical testing or assumptions about the underlying physical processes.

This means users hope their randomness is good enough, but they cannot prove it. Carlos referred to this as faith-based cryptography.

He argued that Level 4 RNGs, which provide quantified uncertainty and real-time entropy verification, are the only path forward for truly secure systems. Unlike Level 3 RNGs, which assume unpredictability, Level 4 RNGs continuously measure and model it, offering an auditable chain of trust.

Implications for Modern Security

Carlos tied this need directly to the NIST Post-Quantum Cryptography (PQC) standards and other global security frameworks. He highlighted that:

• PQC algorithms still depend on entropy. Without strong random seeds, their protections can be bypassed.
• Security modules in defense, telecom, and finance require evidence-based entropy to prevent hidden vulnerabilities.
• Continuous entropy monitoring provides a new class of actionable intelligence for SOCs and NOCs, enabling proactive responses to anomalies in randomness quality.

Key Takeaway

The keynote left attendees with a powerful message: trust in cryptography must move from assumption to verification. Just as we demand proofs for algorithms, we now need proofs for entropy. Quside’s work on Level 4 QRNGs shows that this is no longer a theoretical aspiration—it is a practical capability available today.

Quantum Capture the Flag (Q-CTF): The Entropy Heist

Quside also contributed a challenge to the Quantum Capture the Flag (Q-CTF) competition. For those unfamiliar, a CTF (Capture the Flag) consists of highly challenging tasks where participants must apply their expertise in security and computer systems to recover a hidden piece of information, the “flag.”

Our task, The Entropy Heist, focused on the impact of entropy weaknesses in Post-Quantum Digital Signatures. The task involved performing a brute-force attack to impersonate a given certificate, based on hints about flaws in the entropy source used to generate the certificates.

Participants were asked to:

1. Implement a flawed random generator.
2. Integrate it into a cryptographic library for PQC certificates.
3. Use brute-force techniques to recover private keys.

Participants quickly realized the task was not a simple puzzle. The challenge stood out for its complexity, as it connected one of the most fundamental aspects of cryptography—entropy generation—with advanced concepts such as certificate creation and digital signing. It was not impossible for experienced participants, but even seasoned professionals needed significant effort before solving it.

In the end, the challenge drove home a critical truth: even the strongest algorithms fail if the randomness beneath them is weak.

For those who want to dive deeper, a full write-up of the solution is available here: Entropy Heist CTF Walkthrough.

Looking Ahead

Quside’s participation in DEFCON’s Quantum Village was a unique opportunity to showcase how quantum technologies are shaping the future of cybersecurity. From live demos and hands-on experiences to deep technical talks and competitions, we showed how quantum-grade entropy is becoming a necessity for the digital trust stack.

We’re excited to continue these conversations with the global security community and help organizations adopt quantum-ready, Level 4 RNG solutions to secure the systems of today and tomorrow.