Podcast Summary

TFTC: A Bitcoin Podcast

Episode #733: The Truth About The Quantum Threat with Brandon Black
Host: Marty Bent
Guest: Brandon Black
Date: April 4, 2026

Episode Overview

In this episode, Marty Bent sits down with Bitcoin engineer and FUD-buster Brandon Black to demystify the real and perceived threats posed by advances in quantum computing to Bitcoin’s cryptography. The conversation dives into the technical challenges facing quantum computers, the distinction between mathematical breakthroughs and physical implementation, and the current state of post-quantum cryptography research within the Bitcoin ecosystem.

Key Discussion Points & Insights

1. The Nature of the Quantum Threat

• Perception vs. Reality:

  • Many in the Bitcoin and cryptography communities fear an imminent quantum threat, leading to urgent calls for making Bitcoin “quantum resistant.”
  • Brandon emphasizes a grounded, evidence-based approach, highlighting the immense challenges involved in scaling quantum computers from laboratory curiosities to machines capable of breaking Bitcoin’s cryptographic foundations.

• Quote:

  “I have an emotional confidence that we're 50 to 100 to forever years from a quantum computer breaking a meaningful cryptographic system. But that's not scientific. ... The evidence is it's going to be just hard fought, tiny wins, new technologies. There's just no evidence that it's going to come anytime in the next decade or really any time in the next 20 years.”
  — Brandon, [02:02]

2. Physical vs. Mathematical Progress

• Key Distinction:

  • Theoretical advancements do not equate to practical, physical gains. The leap from scientific breakthroughs to building reliable quantum machines at scale is much larger than most appreciate.
  • Scaling issues are fundamental: each new attempt to increase the number of operational qubits hits unexpected barriers, making exponential growth elusive.

• Quote:

  “There is a chasm between what we can do and the physical reality of building machines that can actually sustain an uptime and persistence to make that theoretical advancement a applicable reality.”
  — Marty Bent, [06:47]

3. Logical vs. Physical Qubits

• Logical Qubits:

  • These are the abstract, error-corrected “working” bits in quantum computation, but realizing each logical qubit requires complex error correction and a much larger bank of unreliable physical qubits.

• Physical Qubits:

  • Highly sensitive, require precise control and stability, and are prone to entropy and decay.

• Quote:

  “These physical qubits, they tend to break down. ... The big question is how do we stabilize them and make it so that we can kind of continue doing computation on them and different Researchers in different parts of the quantum field have different methods of kind of holding that shit together for longer.”
  — Brandon, [12:30]

4. Energy Demands & Scaling

• Orders of Magnitude Away:

  • Even optimistically, building a quantum computer capable of breaking Bitcoin would require scaling up by six to nine orders of magnitude compared to today’s capabilities.
  • The energy and engineering involved could make it intractable given foreseeable technology.

• Quote:

  “He was saying it's something like 100 megawatts ... if you linearly scale up the energy needed per qubit based on current technologies. ... If it's non linear, it may become completely intractable to power a device that can do meaningful quantum computing.”
  — Brandon, [13:17]

5. Bitcoin's Approach to Crypto Upgrades

• No Rushed Changes:

  • There is a significant risk to hastily adopting unproven cryptographic schemes. Changes to address quantum threats must be carefully considered to avoid breaking compatibility with infrastructure like Lightning Network, PSBTs, multisig, and wallet standards.

• Quote:

  “My biggest worry is that you rush a change and it just not only disrupts all of that standardization, that infrastructure that's been built to date, but you haphazardly rush to a change that has [not] been well thought through, well tested, and leads to a bigger fallout in terms of disruption to the network than having done nothing.”
  — Marty Bent, [16:34]

• Ongoing Work:

  • Research continues apace, with new post-quantum algorithms being developed and discussed (e.g., by Jonas Nick and Jonas' Shrimps paper), but nothing is sufficiently mature for deployment yet.

6. Social and Narrative Pressure

• FUD & Panic:

  • Some actors warn in apocalyptic terms about quantum risk—often ahead of real evidence—which risks distracting from meaningful protocol work and potentially stalling other important bitcoin upgrades.

• Quote:

  “I think it's the classic FUD game ... recommend that everyone go read the papers ... the real results being published in the academic papers are small, little nuanced improvements ... now we're seeing tiny results published with huge hype.”
  — Brandon, [31:45]

7. Criteria for Quantum Preparedness

• Evidence-Based Triggers:

  • Brandon suggests clear milestones that should precede action: see one quantum architecture demonstrate repeated, exponential scaling in coherence and qubit count; only then is urgent change warranted.
  • Current progress is far from these triggers.

• Quote:

  “Bitcoin can't be subject to change without evidence that it needs to. ... So we can set a pretty clear evidentiary standard for when a quantum architecture shows these three or maybe four people can argue about exactly what the criteria are, but we can set pretty darn clear standards for the evidence required to start taking immediate action.”
  — Brandon, [55:11]

8. The State of Post-Quantum Crypto for Bitcoin

• Hash-Based, Lattice-Based, & Isogeny-Based Options:

  • Hash-based schemes are most trusted due to reliance on well-understood assumptions but are unwieldy for signatures and current usage patterns.
  • Lattice-based schemes are promising for signature aggregation and speed but are relatively untested, as seen by some broken candidates during the NIST process.
  • Isogeny-based cryptography is an emerging contender and might offer a good balance, but still needs expertise and review.

• Quote:

  “If it's not hash based, we don't know what it would be. It could be lattice, it could be isogeny, it could be something else. And research should continue and is continuing to kind of get to the point where we could do something other than hash based.”
  — Brandon, [44:22]

• On Adding New Cryptosystems:

  • Bitcoin’s conservatism is a strength; upgrades are only considered when they are truly ready and will not jeopardize the network.

Notable Quotes & Memorable Moments

• Brandon’s “ELI5” Summary:

  “The evidence is it's going to be just hard fought, tiny wins, new technologies. There's just no evidence that it's going to come anytime in the next decade or really any time in the next 20 years.” [02:02]

• On Pace of Physical Progress:

  “The biggest improvements have come by implementing whole new architectures. And so there's no evidence right now that any single architecture can increase the number of physical qubits.” [27:53]

• Social Media Hype vs. Reality:

  “When we're getting close. You're going to see the Majorana particle architecture scaled up again ... You're going to see, like, oh, these are big improvements. ... Now we're seeing tiny results published with huge hype. And that's one of the ways to kind of tell how far we are and how much it is just hype.” [31:45]

• On Opportunity Cost:

  “It's essentially fudding the amazing innovations that are still kind of nascent, not widely deployed in Frost and silent payments and music and even DLCs. All of these things are classical elliptic curve based protocols that are really valuable for bitcoin.” [57:15]

• On Social Attacks:

  “I tend to be optimistic on people's motivations, so I don't think so. I think it's more just that people love to panic... it's easy to rile people up with this stuff.” [58:57]

Important Timestamps

• [02:02] – Brandon’s gut feeling & evidence for slow quantum progress
• [06:47] – Marty summarizes the chasm between theory and practical quantum hardware
• [09:04] – Logical vs. physical qubits explained
• [13:17] – Energy scaling and practical constraints
• [16:34] – The risks of rushing quantum-resistance changes in Bitcoin
• [21:32] – The ‘manic’ pressure on Bitcoin developers and reality of who can work on quantum resistance
• [23:42] – Quantum computers are (still) slower than a 6-year-old at factoring
• [27:53] – No orders-of-magnitude leaps; progress comes through new architectures, not scaling
• [36:15] – The cost and risks of hasty protocol changes & the need for evidence
• [41:19] – Shrimps/Shrinks and post-quantum research updates
• [44:22] – Differences and tradeoffs between hash, lattice, and isogeny-based cryptography
• [55:11] – The need for an evidence-based standard for protocol-level urgency
• [57:15] – Potential harm to innovation from overhyping quantum fears
• [58:57] – On whether quantum threat alarmism is an intentional social attack

Conclusion

Both the threat of quantum computers and the urgency to overhaul Bitcoin’s cryptography are often overstated. Practical, scalable quantum attacks remain far off, and Bitcoin development continues to monitor, research, and prepare—at a pace befitting the network’s enormous responsibility and unique risks. There is significant active research and cautious progress toward post-quantum solutions, with a broad consensus that evidence, not hype, will dictate the timeline for Bitcoin's quantum-resistance transition.

For More:

• Follow Brandon (@Erdencode on X)
• Read Bitcoin OpTech for technical breakdowns (summarized weekly by Brandon)
• Check the latest work on Shrimps/Shrinks and other post-quantum algorithms for Bitcoin

Next Steps for Listeners:

• Don’t panic—no need to migrate your keys yet.
• Stay informed and support the ongoing research.
• Focus on immediate, user-facing crypto upgrades (like silent payments, FROST, MuSig, DLCs) that advance the usability and security of Bitcoin today, while remaining vigilant about real (not theoretical) future threats.