Quantum Money and Self-Destructing Signatures — with NTT | Ep. 122

Item: Quantum Money and Self-Destructing Signatures — with NTT | Ep. 122
Rating: 4
Author: PostSingularity Institute

by Konstantinos Karagiannis

Formal & Physical Sciences Science — General & History GPResearch and information: general GPJCoding theory and cryptology

🎙 Konstantinos Karagiannis 👥 1K 📅 February 18, 2026 ⏱ 28 min 👁 95 📄 expert opinion 🧭 2026-08-16

Available in: English (current) Français

Keywords

one-shot signaturesquantum moneyno-cloning theoremindistinguishability obfuscationlearning with errors

Summary

In this episode of The Post-Quantum World, host Konstantinos Karagiannis interviews Omri Shmueli, a cryptographer and postdoctoral research fellow at NTT Research, about one-shot signatures. Shmueli explains that one-shot signatures are a quantum cryptographic primitive that allows a quantum signing key to be used only once, self-destructing after signing a message. This property is rooted in the no-cloning theorem, which prevents copying quantum states. The discussion covers the theoretical foundations, including the work of Steven Wiesner from 1969, and the cryptographic tools used, such as indistinguishability obfuscation (IO) and learning with errors (LWE). The episode explores potential applications, notably quantum money and blockchain scalability. Shmueli describes how one-shot signatures could enable a blockchainless cryptocurrency or reduce the update frequency on a blockchain by using quantum tokens. The conversation also touches on unclonable quantum keys, which can prove that only the holder knows a secret key. The episode highlights the advantages of quantum cryptography, such as provable impossibility of classical simulation, and discusses the challenges, including the need for quantum hardware. Shmueli shares insights into the collaborative research environment at NTT and his future research directions.

185 words

Critical Evaluation

Value of the Information & Strength of the Argument

The value of the information is high, as it provides a clear and accessible explanation of a cutting-edge cryptographic concept. The argumentation is solid, grounded in established principles like the no-cloning theorem and recent research. The guest, Omri Shmueli, is a co-author of a paper that won best paper at Crypto 2025, lending credibility. The discussion is well-structured, moving from basic definitions to applications and implications. The host asks pertinent questions that help clarify complex points, such as the difference between post-quantum and quantum cryptography. The episode also addresses practical considerations, like the need for quantum hardware and potential scalability solutions, making the argumentation comprehensive.

Scientific Rigor, Source Quality, Title Accuracy

The scientific rigor is good, with references to peer-reviewed work and established concepts. The guest cites specific papers and authors, such as Wiesner’s 1969 work and the 2020 paper on one-shot signatures. The quality of sources is high, as the guest is a researcher in the field. The title accurately reflects the content, focusing on quantum money and one-shot signatures. The episode does not delve into detailed technical proofs but provides a high-level overview suitable for an informed audience. The presence of a sponsor (Protiviti) is mentioned but does not affect the content’s integrity. Overall, the sources are credible and the title is appropriate.

224 words

Title / Content Match

The title accurately reflects the content, focusing on quantum money and one-shot signatures.

Quality & Reliability

7/10

The episode features a postdoctoral researcher discussing a peer-reviewed paper (Crypto 2025). The content is technically accurate and well-explained, but it is a podcast interview with limited depth and no formal verification of claims.

Key Moments

Markers derived by PSI from the transcript: the creator did not define chapters.

Cited Sources

NTT Research — Mentioned as the research institution where Omri Shmueli works
Protiviti Quantum Computing Services — Sponsor and host's employer, mentioned in description

Concurring Sources

No-cloning theorem — Supports the impossibility of cloning quantum states, a key premise of one-shot signatures.
Quantum money — Historical context for the applications discussed in the episode.

Contribution & Novelties

The episode provides an accessible explanation of one-shot signatures, a recent advancement in quantum cryptography. It highlights the potential for quantum money and blockchain scalability, offering a novel perspective on how quantum properties can be leveraged for cryptographic applications. The discussion with a researcher directly involved in the work adds depth and credibility.

Pour aller plus loin :

No-cloning theorem — Foundational principle behind one-shot signatures.
Quantum money — Historical concept dating back to Wiesner.
Indistinguishability obfuscation — Cryptographic tool used in the construction.
Learning with errors — Computational problem central to post-quantum cryptography.

94 words

Radar Profile

The radar profile shows a balanced performance across all dimensions, with slightly higher scores in quality of information and technical level, indicating a well-explained and technically sound episode. The lower score in quantity of information reflects the concise duration and focused scope.

Reliability 7/10

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