Semi-quantum Tokenized Signatures

Shmueli, Omri

doi:10.1007/978-3-031-15802-5_11

Cited by 11 publications

(20 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To broaden the applicability of our semi-quantum protocol, we also present in this work a semi-quantum tokenized signature scheme with strong unforgeability (i.e., no efficient adversary can output two different signatures even for the same message). Previous constructions of [CLLZ21] and [Shm22b] do not consider strong unforgeability and are only proven to be weakly unforgeable. Our quantum protocol of strongly unforgeable tokenized signature scheme is indeed the same as the one for weak unforgeability given in [CLLZ21].…”

Section: Our Resultsmentioning

confidence: 99%

“…Indeed, to the best of our knowledge, all known provably secure copy-protection schemes with standard malicious security are based on hidden coset states [CLLZ21, AKL + 22]. 2 Using application-specific approaches, Shmueli further gives several semi-quantum protocols from coset states for public-key quantum money in [Shm22a] and tokenized signatures in [Shm22b]. Even though both are based on hidden coset states, his constructions are tailor-made for these applications.…”

Section: Can We Construct Semi-quantum Copy-protection With Standard ...mentioning

confidence: 99%

“…Even though both are based on hidden coset states, his constructions are tailor-made for these applications. For example, in the case of semi-quantum tokenized signature, the signature generation process in Shmueli's protocol ( [Shm22b]) is defined specifically for the application, and it is quite different from the quantum construction given in [CLLZ21]. On the other hand, modularity and generic approaches are highly desirable in cryptography, and thus our second question in this work is:…”

Section: Can We Construct Semi-quantum Copy-protection With Standard ...mentioning

confidence: 99%

See 2 more Smart Citations

Semi-quantum Copy-Protection and More

Chevalier,

Hermouet,

2023

Lecture Notes in Computer Science

View full text Add to dashboard Cite

Properties of quantum mechanics have enabled the emergence of quantum cryptographic protocols achieving important goals which are proven to be impossible classically. Unfortunately, this usually comes at the cost of needing quantum power from every party in the protocol, while arguably a more realistic scenario would be a network of classical clients, classically interacting with a quantum server.In this paper, we focus on copy-protection, which is a quantum primitive that allows a program to be evaluated, but not copied, and has shown interest especially due to its links to other unclonable cryptographic primitives. Our main contribution is to show how to dequantize quantum copy-protection schemes constructed from hidden coset states, by giving a construction for classically-instructed remote state preparation for coset states, which preserves hardness properties of hidden coset states. We then apply this dequantizer to obtain semi-quantum cryptographic protocols for copy-protection and tokenized signatures with strong unforgeability. In the process, we present the first secure copy-protection scheme for point functions in the plain model and a new direct product hardness property of coset states which immediately implies a strongly unforgeable tokenized signature scheme.⋆ Work done while at CRED and DIENS. 1 This is called hybrid quantum cryptography in [AGKZ20]. Technical Overview Our Remote Coset State Preparation Protocol and Its Application toCopy-ProtectionIn this section, we give an overview of our remote coset state preparation protocol and its proof of soundness. To give the reader a glimpse of the functionality of our protocol and how it can be used as a generic compiler to obtain semi-quantum copy-protection, we first start by analysing security requirements for several existing quantum copy-protection schemes based on coset states.Security Requirements. For our discussion, we focus on the copy-protection of pseudorandom functions scheme in the plain model and the single-decryptor scheme in the plain model presented in [CLLZ21]. The common point is that security of these constructions all reduce to a monogamy-ofentanglement property of coset states [CLLZ21, CV22]. Informally, this property states that a triple of quantum algorithms Alice, Bob and Charlie cannot cooperatively win the following monogamy game with a challenger, except with negligible probability. The challenger first prepares a uniformly random coset state |A s,s ′ ⟩ and gives the state to Alice. Alice outputs two (possibly entangled) quantum states and sends them to Bob and Charlie respectively. No communication is allowed between Bob and Charlie. Finally, Bob and Charlie both get the description of the subspace A. The game is won if Bob outputs a vector in A + s and Charlie outputs a vector in A ⊥ + s ′ , where A ⊥ denote the dual subspace of A.If our goal is to design a semi-quantum protocol for preparing coset states such that it can be used in a plug-and-play manner for the aforementioned protocols, our protocol needs to have the fo...

show abstract

Section: Our Resultsmentioning

confidence: 99%

Section: Can We Construct Semi-quantum Copy-protection With Standard ...mentioning

confidence: 99%

Section: Can We Construct Semi-quantum Copy-protection With Standard ...mentioning

confidence: 99%

See 1 more Smart Citation

Semi-quantum Copy-Protection and More

Chevalier,

Hermouet,

2023

Lecture Notes in Computer Science

View full text Add to dashboard Cite

show abstract

“…Recently, Shmueli [Shm22b] proved a variant of tokenized signatures which is called semi-quantum tokenized signatures. Semi-quantum money is a quantum money scheme in which the minting is done in an interactive protocol between the user and a classical bank [RS22,Shm22a].…”

Section: Subsequent Workmentioning

confidence: 99%

Quantum Tokens for Digital Signatures

Ben-David

Sattath

2023

Quantum

View full text Add to dashboard Cite

The fisherman caught a quantum fish. "Fisherman, please let me go", begged the fish, "and I will grant you three wishes". The fisherman agreed. The fish gave the fisherman a quantum computer, three quantum signing tokens and his classical public key. The fish explained: "to sign your three wishes, use the tokenized signature scheme on this quantum computer, then show your valid signature to the king, who owes me a favor". The fisherman used one of the signing tokens to sign the document "give me a castle!" and rushed to the palace. The king executed the classical verification algorithm using the fish's public key, and since it was valid, the king complied. The fisherman's wife wanted to sign ten wishes using their two remaining signing tokens. The fisherman did not want to cheat, and secretly sailed to meet the fish. "Fish, my wife wants to sign ten more wishes". But the fish was not worried: "I have learned quantum cryptography following the previous story (The Fisherman and His Wife by the brothers Grimm). The quantum tokens are consumed during the signing. Your polynomial wife cannot even sign four wishes using the three signing tokens I gave you". "How does it work?" wondered the fisherman. "Have you heard of quantum money? These are quantum states which can be easily verified but are hard to copy. This tokenized quantum signature scheme extends Aaronson and Christiano's quantum money scheme, which is why the signing tokens cannot be copied". "Does your scheme have additional fancy properties?" the fisherman asked. "Yes, the scheme has other security guarantees: revocability, testability and everlasting security. Furthermore, if you're at sea and your quantum phone has only classical reception, you can use this scheme to transfer the value of the quantum money to shore", said the fish, and swam away.

show abstract

“…• In the second category, we have constructions based on well-studied (or perhaps better -studied) cryptographic primitives. In this category, we have constructions [Zha21;Shm22a;Shm22b] based on indistinguishability obfuscation, first initiated by Zhandry [Zha21].…”

Section: Introductionmentioning

confidence: 99%

On the (Im)plausibility of Public-Key Quantum Money from Collision-Resistant Hash Functions

Ananth¹,

Hu²,

Yuen³

2023

Preprint

View full text Add to dashboard Cite

Public-key quantum money is a cryptographic proposal for using highly entangled quantum states as currency that is publicly verifiable yet resistant to counterfeiting due to the laws of physics. Despite significant interest, constructing provably-secure public-key quantum money schemes based on standard cryptographic assumptions has remained an elusive goal. Even proposing plausibly-secure candidate schemes has been a challenge.These difficulties call for a deeper and systematic study of the structure of public-key quantum money schemes and the assumptions they can be based on. Motivated by this, we present the first black-box separation of quantum money and cryptographic primitives. Specifically, we show that collision-resistant hash functions cannot be used as a black-box to construct publickey quantum money schemes where the banknote verification makes classical queries to the hash function. Our result involves a novel combination of state synthesis techniques from quantum complexity theory and simulation techniques, including Zhandry's compressed oracle technique.

show abstract

Semi-quantum Tokenized Signatures

Cited by 11 publications

References 7 publications

Semi-quantum Copy-Protection and More

Semi-quantum Copy-Protection and More

Quantum Tokens for Digital Signatures

On the (Im)plausibility of Public-Key Quantum Money from Collision-Resistant Hash Functions

Contact Info

Product

Resources

About