Coefficient Grouping for Complex Affine Layers

ePrint Report: Coefficient Grouping for Complex Affine Layers

Fukang Liu, Lorenzo Grassi, Clémence Bouvier, Willi Meier, Takanori Isobe

Designing symmetric-key primitives for applications in Fully Homomorphic Encryption (FHE) has become important to address the issue of the ciphertext expansion. In such a context, cryptographic primitives with a low-AND-depth decryption circuit are desired. Consequently, quadratic nonlinear functions are commonly used in these primitives, including the well-known $\chi$ function over $\mathbb{F}_2^n$ and the power map over a large finite field $\mathbb{F}_{p^n}$. In …

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