Description
The CL encryption scheme, proposed in 2015 by Castagnos and Laguillaumie, is a linearly homomorphic encryption scheme, based on class groups of imaginary quadratic fields. The specificity of these groups is that their order is hard to compute, which means it can be considered unknown. This particularity, while being key in the security of the scheme, brings technical challenges in working with CL, especially in the design of zero-knowledge protocols.
To overcome these difficulties, we define a new notion of soundness, called soundness with partial extractability, that is especially suited to the CL framework. Thanks to partial extractability, we design efficient zero-knowledge proofs and arguments for different CL-related statements. In this talk, after motivating the necessity of efficient protocols in the CL context, I will introduce this new notion and present a batched proof of correct encryption.
Infos pratiques
Prochains exposés
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TBA
Orateur : Eran Lambooij - Inria
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Cryptography
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Key Attack on the ACDGV Matrix Encryption Scheme
Orateur : Anmoal Porwal - Technical University of Munich
I will present our key-recovery attack on the ACDGV public-key encryption scheme proposed at ASIACRYPT 2024 by Aragon, Couvreur, Dyseryn, Gaborit, and Vinçotte. The secret key is a Gabidulin code hidden by appending random rows and columns and by left- and right-multiplication with invertible matrices. Our attack exploits the resulting algebraic structure to recover an equivalent secret key. It[…]-
Cryptography
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Asymmetric primitive
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