Revisiting TESLA in the quantum random oracle model Selected - - PowerPoint PPT Presentation

revisiting tesla in the quantum random oracle model
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Revisiting TESLA in the quantum random oracle model Selected - - PowerPoint PPT Presentation

Revisiting TESLA in the quantum random oracle model Selected history of Fiat-Shamir style signatures from LWE or SIS Lyubashevsky 2012 Sigs via Fiat-Shamir Bai-Galbraith BLISS 2013 Short sigs Optimized DBGGOPSS 2014 Improvements,


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Revisiting TESLA in the quantum random oracle model

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Selected history of Fiat-Shamir— style signatures from LWE or SIS

2012 2013 2015 2014 Lyubashevsky Sigs via Fiat-Shamir Bai-Galbraith Short sigs BLISS Optimized DBGGOPSS Improvements, fast implementation TESLA Tight security reduction, fast implementation ring-TESLA Now with rings, fast implementation TESLA# Improvements, fast implementation 2016

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Selected history of Fiat-Shamir— style signatures from LWE or SIS

2012 2013 2015 2014 Lyubashevsky Sigs via Fiat-Shamir Bai-Galbraith Short sigs BLISS Optimized DBGGOPSS Improvements, fast implementation TESLA Tight security reduction, fast implementation ring-TESLA Now with rings, fast implementation TESLA# Improvements, fast implementation 2016 This talk

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Preamble

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Given a forger...

Forger Sign

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...construct a P-solver

Forger

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Parameter choice should account for the security reduction

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Tightness

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The quantum random oracle model (QROM)

Hash

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When does ROM imply QROM?

Boneh, Dagdelen, Fischlin, Lehmann, Schaffner, Zhandry

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Prior work on TESLA

Lyubashevsky Sigs via Fiat-Shamir Bai-Galbraith Short sigs BLISS Optimized DBGGOPSS Improvements, fast implementation TESLA Tight security reduction, fast implementation ring-TESLA Now with rings, fast implementation TESLA# Improvements, fast implementation Reduction from LWE, SIS. Proof uses Forking Lemma. Non-tight, re-programming. ROM but not QROM. Reduction from LWE only. Tight reduction in ROM. QROM via chameleon hash functions.

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Our contributions (theoretical)

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Our contributions (practical)

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Summary of related work

Abdalla, Fouque, Lyubashevsky, Tibouchi Katz, Wang Gentry, Peikert, Vaikuntanathan Boyen, Li

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“Lattice-based” crypto

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“Lattice-based” crypto

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Learning with Errors (LWE) (matrix version)

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TESLA key generation

Pk: LWE yes-instance Sk: witness

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TESLA sign

Zero-knowledge proof (S,E) + Fiat-Shamir

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TESLA sign: terminology

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TESLA verify

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Security theorem for TESLA

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Security theorem for TESLA

Tightness: Scaling factor 1.

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Proof overview

Forger Sign Hash

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Simulator

Sign Hash Simulator

classical quantum classical quantum

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Forger forges, even with a simulator

Forger Simulator

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Forger + Simulator = LWE solver

Forger Simulator

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Forger + Simulator = LWE solver

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Yes-instances: Signature simulator

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Yes-instances: Signature simulator

Re-program a quantum oracle!

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Re-programming in TESLA

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No-instances: Good hash inputs

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Search through unstructured space

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Good hash inputs are rare

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Parameter sets

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Parameter sets

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Software

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Global A matrix?

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Proof approach

Abdalla, Fouque, Lyubashevsky, Tibouchi

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Other tightly-secure LWE or SIS signatures (move to the end?)

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Comparison: LWE/SIS schemes

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Comparison: hash-based schemes